wet skimming vs. dry skimming... [Archive] - Reef Central Online Community Archives

Fatboy

09/27/2005, 07:25 AM

Originally posted by Reeferee
I will switch to a drier skim in an effort to be more precise in removing organics.

I'm reviving this thread because I'm intrigued with this last comment.

For a long time I've been trying to determine what is better for my tank....... to run a wet or dry skimmer, but I still don't find any evidence that will say that one way is better that the other one.

How could a drier skim be more precise or better for removing organics ? What would be the physical or chemical explanation for this ?

On a great thread started by Anthony Calfo, he says that wet skimming is better for retiring suspended material (detritus) from the water column, but that a drier foam is better for pulling out DOM.

I have also read that a lot o people with algae or ciano problems, after they started to run their skimmers on the wetter side, their problem went away and at least for me, this is completely opposite to what Anthony Calfo is saying.

Any hard evidence around ?

I'm running a wetter foam basically for two reasons:

1.- I don't' like all the gunk to stay on the skimmer raising tube since all that organic matter that stays in there, could be processed by bacteria and in some way, be leached back to the tank. I prefer all my gunk in the collection cup were bacteria can do whatever they want with it. (maybe I'm wrong with this theory..... who knows).

2.- In order to run a skimmer on the wetter side, you have to inject more air. In some skimmers, that would create some bigger bubbles but is some other ones, the size of the bubble is not affected by the amount of air. Could it be that if the bubbles stays at the same size, by having more bubbles in your reaction chamber, you will have a bigger surface to attract organics ? Shouldn't this be more effective for retiring organics from the water ?

All your comments are welcome (and specially..... hard evidence if there¡s any).

Bomber

09/27/2005, 08:43 AM

Originally posted by Fatboy
How could a drier skim be more precise or better for removing organics ? What would be the physical or chemical explanation for this ?

On a great thread started by Anthony Calfo, he says that wet skimming is better for retiring suspended material (detritus) from the water column, but that a drier foam is better for pulling out DOM.

There's a lot of confusion about this. I think mainly because people don't think about a skimmer and how they work.

What you have is a cannister filter with a filter media in it, just like running carbon or chemical media in a canister filter. Only the filter media is foam.

Water is circulated through the media - foam - just like you would use carbon - and returned to the system. You rely on that foam just like any other filter media.

Which would remove more? Old dirty carbon? old dirty bubbles?

Or fresh clean bubbles with a more highly reactive surface?

The wetter you run the skimmer, the more fresh clean bubbles you have, the faster it will remove DOM. Just like fresh clean carbon will remove more.

Plus, running it wetter will also move particulate detritus up and over the riser which takes out even more.

Drier foam will not pull out more faster. It just concentrates it and makes it look that way. The older, dirtier bubbles will take up a lot less.

Cosper

09/27/2005, 09:27 AM

Speaking of skimmers... I added some kind of water condidtioner that has an ingredient that my skimmer definitly doesnt like. It just foams like crazy.. flooding the collection cup with water. I havent been able to run the skimmer for about three days now. How long will it take for this to run its course?

vitz

09/27/2005, 09:46 AM

Originally posted by Bomber
There's a lot of confusion about this. I think mainly because people don't think about a skimmer and how they work.

What you have is a cannister filter with a filter media in it, just like running carbon or chemical media in a canister filter. Only the filter media is foam.

Water is circulated through the media - foam - just like you would use carbon - and returned to the system. You rely on that foam just like any other filter media.

Which would remove more? Old dirty carbon? old dirty bubbles?

Or fresh clean bubbles with a more highly reactive surface?

The wetter you run the skimmer, the more fresh clean bubbles you have, the faster it will remove DOM. Just like fresh clean carbon will remove more.

Plus, running it wetter will also move particulate detritus up and over the riser which takes out even more.

Drier foam will not pull out more faster. It just concentrates it and makes it look that way. The older, dirtier bubbles will take up a lot less.

any actual empirical evidence to back this up ?

romanr

09/27/2005, 09:48 AM

I wish someone would do a controlled study to settle this issue once and for all. It seems like all we have at this point is anecdotal evidence and some mighty fine reasoning for why one is better than the other.

sellout007

09/27/2005, 10:38 AM

Originally posted by Cosper
Speaking of skimmers... I added some kind of water condidtioner that has an ingredient that my skimmer definitly doesnt like. It just foams like crazy.. flooding the collection cup with water. I havent been able to run the skimmer for about three days now. How long will it take for this to run its course?

It wont go away, its the slime coat in the dechlorinator. You need to run your skimmer until it takes it all out. Mine took about an hour or two and then it was fine.

Go and get new dechlorinator, one wihtout a slime coat. o)

BTW just sit by your skimmer and empty the cup each time it fills.

sellout007

09/27/2005, 10:41 AM

Originally posted by Bomber
Drier foam will not pull out more faster. It just concentrates it and makes it look that way. [/B]

Originally posted by vitz
any actual empirical evidence to back this up ?

If you think about it, it makes sense.

Why would a drier foam be more effective? Take 5 gallons of water and add100 drops of red dye to it. Take 1 gallon of water and add100 drops of red dye.

Tell me which *looks* more red. But the fact is they both still have the same amount of drops. Just one is more diluted so it appears one has more red in it.

Same with skimming. When you skim wet, you empty your cup more often. There is more *water* involved so it fills up faster and looks diluted. When you skim dry it just takes longer to fill the cup up.

Im not so sure about the bubbles being newer so they work better. Id have to sit and think about that one for a while. But I do agree that when skimming wet you get more particlues of food and detritus.

Fatboy

09/27/2005, 11:10 AM

Bomber,

As usual...... you have been very helpful. Dou think that by leaving all that gunk in the raising tube, some elements could be leached back to the aquarium (by the action of bacteria ) ?

BloBBeBo

09/27/2005, 11:55 AM

I prefer dry foam because of my paranoid of it overflowing, lol. I don't really know how to set it to dry or wet though? I usually keep the water level at around the neck. Sometimes it makes good bubbles, but other times the bubbles just pop immediately when they hit the surface of the water, they don't have time to go up the column? Why does it do that? It doesn't skim anything when it does that -_-

HippieSmell

09/27/2005, 12:02 PM

Originally posted by Fatboy
On a great thread started by Anthony Calfo, he says that wet skimming is better for retiring suspended material (detritus) from the water column, but that a drier foam is better for pulling out DOM.

That would make sense. Skimming dry would be more selective towards removing polar material, like protein, whereas wet will remove both polar and some non-polar stuff, like poop.

BloBBeBo

09/27/2005, 12:21 PM

http://img192.imageshack.us/img192/492/mvc037s7yx.jpg

Sooo annoying :| Why does it do that and how do I make it like..make more bubbles or stop them from popping so soon?

Puffers

09/27/2005, 12:40 PM

I'm not sure how an experiment could be done to prove this one way or the other. There may be a better method of running a skimmer depending upon the tank it is set-up in (DSB vs no SB).

I have run dry and wet, the only difference I have noticed thus far is bigger particles are in the collection cup when skimming wet. My trates are the same as before though I do have a fuge.

For me it's all about prevention in this hobby. By capturing more and larger particles before they break down and rot will help my tanks long term health. Therefore I like to skim wet.

Bomber is there a protein/bacterial test or experiment that could give a measured value of skimmers effectiveness? Or do we use something else, if so what?
:confused:

vitz

09/27/2005, 02:39 PM

quote:
--------------------------------------------------------------------------------
Originally posted by Bomber
Drier foam will not pull out more faster. It just concentrates it and makes it look that way. [/B]
--------------------------------------------------------------------------------

quote:
--------------------------------------------------------------------------------
Originally posted by vitz
any actual empirical evidence to back this up ?
--------------------------------------------------------------------------------

Originally posted by sellout007
If you think about it, it makes sense.

Why would a drier foam be more effective? Take 5 gallons of water and add100 drops of red dye to it. Take 1 gallon of water and add100 drops of red dye.

Tell me which *looks* more red. But the fact is they both still have the same amount of drops. Just one is more diluted so it appears one has more red in it.

Same with skimming. When you skim wet, you empty your cup more often. There is more *water* involved so it fills up faster and looks diluted. When you skim dry it just takes longer to fill the cup up.

Im not so sure about the bubbles being newer so they work better. Id have to sit and think about that one for a while. But I do agree that when skimming wet you get more particlues of food and detritus.

if i think about it, i realize that no one here is likely to be non-ignorant about bubble physics-it only makes sense because of what we think we may know about bubbles, and it may be completely different in reality

it makes sense to ME that dry skimming is more efficient than wet skimming, and no one can say for sure that the bubbles are coated fully, or even halfway, when dry skimming, and that adding more fresh bubbles improves removal of anything ;)

so i re-iterate-what empirical evidence is there to back up the assertion that a more frequent influx of fresh bubbles actually improves the overall amount of bubbles' ability to remove protienaceous matter? has anyone done measurements on the surface of the bubbles themselves to see how relatively coated they actually get whet wet vs dry skimming?

until such evidence is available i personally believe that wet skimmings 'apparent' better performance is just that-apparent ;)

sellout007

09/27/2005, 02:43 PM

Originally posted by vitz
if i think about it, i realize that no one here is likely to be non-ignorant about bubble physics-it only makes sense because of what we think we may know about bubbles, and it may be completely different in reality

it makes sense to ME that dry skimming is more efficient than wet skimming, and no one can say for sure that the bubbles are coated fully, or even halfway, when dry skimming, and that adding more fresh bubbles improves removal of anything ;)

so i re-iterate-what empirical evidence is there to back up the assertion that a more frequent influx of fresh bubbles actually improves the overall amount of bubbles' ability to remove protienaceous matter? has anyone done measurements on the surface of the bubbles themselves to see how relatively coated they actually get whet wet vs dry skimming?

until such evidence is available i personally believe that wet skimmings 'apparent' better performance is just that-apparent ;)

Ok so why dont you tell me why you think skimming dry is more efficient? What evidence do you have? Because your skimmate is darker and thicker? So because it lacks more water its better? Even though it takes longer to accumulate?

Im not even talking about *fresh bubbles*. I am talking about simple dilution. Nothing more.

The only reason I think skimming *wet* would be better is bceause it takes out large particles more then *dry* skimming. When I skim wet I see chunks of food and detritus. That would be the only evidence that I could argue.

Im not saying one is better then the other, Im simply saying that just because your skimmate is thick, doesnt mean its better.

vitz

09/27/2005, 02:45 PM

i think it's more efficient because the energy inputted is going less towards water removal, when dry skimming

sellout007

09/27/2005, 02:48 PM

Originally posted by vitz
i think it's more efficient because the energy inputted is going less towards water removal, when dry skimming

What??? :)

Sorry but I dont understand exactly what you mean. Your saying that skimming dry, the skimmer uses its energy to remove crap, instead of water. And when you skim wet the skimmer is using its *energy* to remove water isntead?

vitz

09/27/2005, 02:49 PM

i'm saying that more energy is being diverted to removing plain water, when wet skimming

sellout007

09/27/2005, 02:53 PM

Ok. I agree that more water is removed when skimming wet. But as I said earlier in my *red dye* example, the end product is the same.

You may fill up one cup a week when dry skimming, and fill 3 cups skimming wet. But the amount of actual *junk* is still the same. It just so happens that its diluted with 3 cups of water so it *looks* like its not as much.

See what I am saying?

vitz

09/27/2005, 03:00 PM

er- the end product is the same, but more energy was used = less efficient ;)

sellout007

09/27/2005, 03:09 PM

Originally posted by vitz
er- the end product is the same, but more energy was used = less efficient ;)

Good try, but no. O)

Do you turn your skimmer off at all? Then your using the same amoutn of energy to remove the same amount of organics. It just so happens more water comes with wet skimming.

The end product still produces the same amount of gunk, organics whatever you want to call it, and the skimmer still uses the same amount of energy.

The only downfall (if youw ant to call it that) would be that you have to replace the water that is taken out.

The bonuses, skimming wet pulls out more *full* or *whole* pieces of gunk. Uneten food, detritus etc etc.

trippyl

09/27/2005, 03:48 PM

Efficiency always comes at a price - performance. There is an old engineering saying in computers:

You can have a speedy process, you can have an efficient process, or you can have a process built quickly. Choose two.

If you want effiency, then it will come at a cost of performance. No question that there is a curve here, where efficiency comes at the cost of removing as much waste as possible. After all, who hasn't run their skimmer too dry? Red dye drop argument aside, I'd rather run my skimmer wet, which would be less efficient, use more power, but indiscriminantly take out more nasty water. I'd be the first to agree that wet skimming doesn't make that much of a difference at all, but I could use all the help I can get.

sellout007

09/27/2005, 03:51 PM

See thats what I dont understand...

Why would you assume that the skimmer is using more power when it skims wet? *lol*

The skimmer (pump) uses the same amount of volts no matter what. Even if it wasnt hooked up to a skimmer. So it uses the same amount of energy?

Or are we using *power* and *energy* as meaning something different?

I think that skimming wet or dry produces the same kind of or amount of gunk made by the bubbles, but when skimming wet you get the added benefits of taking out large pieces of food or detritus as well.

NoSchwag

09/27/2005, 04:19 PM

Isn't skimming wet just closing the gate valve to get the water in the column higher? If anything I would thing it used less energy.. ::scratches head::

Weatherman

09/27/2005, 04:31 PM

Originally posted by NoSchwag
Isn't skimming wet just closing the gate valve to get the water in the column higher? If anything I would thing it used less energy.. ::scratches head::

By closing off the gatevalve, you are restricting outflow from the skimmer. This causes greater backpressure on the pump resulting in a higher water column. It's not much, but the pump does have to work harder to keep the water column in the skimmer higher.

MiddletonMark

09/27/2005, 04:45 PM

Originally posted by Weatherman
By closing off the gatevalve, you are restricting outflow from the skimmer. This causes greater backpressure on the pump resulting in a higher water column. It's not much, but the pump does have to work harder to keep the water column in the skimmer higher.

But running the level high with very dry skimmate, or lower with very water skimmate [difference of injected air] ... would yield wet skimming more efficient if the gate valve would be open more.

Sure seems to me, that wet/dry matters not - that the amount of pressure [from restricted outflow] would be a bigger input that the air/water relationship [wet vs. dry].

--
And when you think about it, ultra dry would probably be least efficient in terms of DOM/particulate/skimmate collected vs. power used.

Weatherman

09/27/2005, 04:52 PM

Originally posted by MiddletonMark
But running the level high with very dry skimmate, or lower with very water skimmate [difference of injected air] ... would yield wet skimming more efficient if the gate valve would be open more.

Sure seems to me, that wet/dry matters not - that the amount of pressure [from restricted outflow] would be a bigger input that the air/water relationship [wet vs. dry].

--
And when you think about it, ultra dry would probably be least efficient in terms of DOM/particulate/skimmate collected vs. power used.

I completely forgot about controlling the air input. (You'd think I'd know better since I have a Bullet 3.)

Sure, just open the air input valve to inject more air. You'll get more bubbles and it will lift the water column higher without giving it more weight. You'll get wetter output that way with no significant additional energy required.

trippyl

09/27/2005, 05:12 PM

Here is another thought, is it possible that skimming wet means more bubbles coming in contact with water, more oxygenation, etc.

And a few of you are right, wet skimming could be done with no additional power, but that depends on the model. With my remora pro, there'd be no way I could skim wet unless I used the mag 7 instead of the mag 3 (which never really allowed me to skim wet). That was the increase in power I was speaking of.

photobarry

09/27/2005, 07:47 PM

My skimming observations:

-Using clean fresh seawater your skimmer shouldn't skim anything. This is how I think people should calibrate their skimmers, but I don't know anyone that does. I recommend breaking in a new skimmer in freshly made SW and testing to see how much you can turn it up before it bubbles/foam overflow into the collection cup. Then you know how your skimmer acts in clean water and can compare that to your tank.

-If you are running your skimmer to get dark/dry skimmate, what happens when you try to get it to skim wetter? IME the skimmer goes crazy and overflows alot. (Indicating a higher level of available organics in the water.)

-If you start from day one with a skimmer set to skim "wet", it should always skim at about the same level, even if it is dialed-in to the calibrated level for clean SW. (Suggesting it is effectively removing organics from the water.)

fishamajiggle

09/27/2005, 09:25 PM

I actuially run (2) skimmers

the larger of the 2 is dry skimming (for some reason i cant make it skim wet)

and the smaller of the 2 skims wet and i have to empty it every day

with the combination of the two i feel i get a good result

may not be the most practical but it works so far.

Skepperz

09/27/2005, 10:27 PM

Anyone tried running 2 skimmers?

Maybe one wet and one dry?

Could this mean more efficient skimming?

Or could they just cancel another out.

Just a thought

fishamajiggle

09/27/2005, 10:33 PM

i just said that

NoSchwag

09/27/2005, 10:41 PM

Originally posted by Weatherman
I completely forgot about controlling the air input. (You'd think I'd know better since I have a Bullet 3.)

Tsk Tsk Tsk.. You're slacking ;)

Skepperz

09/27/2005, 10:59 PM

Ha i think that we posted at the same time fishamajiggle, i din't see your post when i put mine up.

fishamajiggle

09/27/2005, 10:59 PM

no prob :lol:

Skepperz

09/28/2005, 12:02 AM

Working too hard forgot to hit the refresh button! lol!

Airman

09/28/2005, 12:27 AM

I like to dry skim. I can see a difference in the foam day to day. Some days are heavy some days are light. Can you see a difference with wet skimming?

sellout007

09/28/2005, 12:37 AM

Originally posted by Airman
I like to dry skim. I can see a difference in the foam day to day. Some days are heavy some days are light. Can you see a difference with wet skimming?

Just curious, whats the advantage of being able to see the difference from day to day?

Or are you just asking a question? o)

photobarry

09/28/2005, 12:57 AM

Originally posted by Airman
I like to dry skim. I can see a difference in the foam day to day. Some days are heavy some days are light. Can you see a difference with wet skimming?

Wet skimming doesn't let nutrients build up to the point where you would get day to day differences.

Ereefic

09/28/2005, 09:07 AM

I'm running an MR-1 and when I skim wetter, the neck remains relativly clear (no scum build-up). In the waste collector (1 gal.) the liquid is a yellowish/brownish icky color and there is a minimal amount of particular matter in the bottom of it.

Now, when I skim a little dryer, the neck gets a thick layer of gunk. The overall production of liquid in the waste collector is about half of that of wet skimming. The skimmate is dark brown, and appears to have roughly the same amount of particulate matter in it.

Just from these observations, it would seem that dry skimming is taking out more gunk, just by the amount of crud built up on the skimmer neck. I can scrap off a 1/8"-1/4" think layer of gunk that i'm not getting out by skimming wet. Yet total amount of particulate in the waste collector is roughly the same, only the liquid amount is more.

Am I way off base on my thinking?

Puffers

09/28/2005, 11:44 AM

Part of the issue I think is not all skimmers are the same nor is everybody's tank loads. IMO if dry or wet skimming did remove more "gunk" and proteins out of the water then we should see a noticeable impact on wq. My guess is that out home test kits are not dialed in to be that precise to see the difference.

For me skimming wet I can get larger and more particles out of the water column before it can rot and break down in the tank.

Good thing I bought that needle value skimmer so I can get larger particles out of the water!:D :D :) :D :cool:

vitz

09/28/2005, 12:18 PM

Originally posted by sellout007
See thats what I dont understand...

Why would you assume that the skimmer is using more power when it skims wet? *lol*

The skimmer (pump) uses the same amount of volts no matter what. Even if it wasnt hooked up to a skimmer. So it uses the same amount of energy?

Or are we using *power* and *energy* as meaning something different?

I think that skimming wet or dry produces the same kind of or amount of gunk made by the bubbles, but when skimming wet you get the added benefits of taking out large pieces of food or detritus as well.

you seem to either miss, or ignore, my point

the issue i'm dealing with is removal of protiens per volume of material removed per x amount of energy used by the skimmer

if more material is being removed-something has to lower as a function of the percentage of the volume of that amount of material, and it takes more energy to lift a cup of water out of a skimmer than 1/2 cup of water

if the amount of protien is the same (and i've yet to see/read/hear of anything contrary to this), then more energy was required by the skimmer to remove that same amount of protien, since in one case it also removed more water, which requires more energy

vitz

09/28/2005, 12:25 PM

Originally posted by trippyl
Here is another thought, is it possible that skimming wet means more bubbles coming in contact with water, more oxygenation, etc.

And a few of you are right, wet skimming could be done with no additional power, but that depends on the model. With my remora pro, there'd be no way I could skim wet unless I used the mag 7 instead of the mag 3 (which never really allowed me to skim wet). That was the increase in power I was speaking of.

no studies have been done that would even hint at the amount of bubbles being used in dry skimming to be inadequate for the removal of protiens present-again-one needs to first find out if the amount of bubbles used in dry skimming are already maxing out for their potential space to accept protiens

adding 8x's the amount of bubbles will increase the removal by 8x's only if the coating of the bubbles stays constant, and it's possible that there is no efficiency/removal gained whatsoever

bubble physics has not been addressed in anyone's claim that wet skimming removes more protiens than dry

wet skimming may remove more phytoplankton, , or it may not-could be the same amount is also removed via dry skimming, but visually, doesn't seem that way

one really needs to compare equal amounts of dry and wet skimmate per unit of time to do a comparative analysis of waste material removed per type of skimming

i.e.-2 hrs of wet skimmate collection vs two hrs of dry, then measure the watse products-that would gve a fair initial indication of wich method is better, overall-a visual impression is absolutely useless ;)

photobarry

09/28/2005, 12:44 PM

Originally posted by vitz
bubble physics has not been addressed in anyone's claim that wet skimming removes more protiens than dry

wet skimming may remove more phytoplankton, , or it may not-could be the same amount is also removed via dry skimming, but visually, doesn't seem that way

one really needs to compare equal amounts of dry and wet skimmate per unit of time to do a comparative analysis of waste material removed per type of skimming

Without this analysis, why do you believe dry skimming is more effective than wet?

sellout007

09/28/2005, 12:52 PM

Originally posted by vitz
you seem to either miss, or ignore, my point

the issue i'm dealing with is removal of protiens per volume of material removed per x amount of energy used by the skimmer

if more material is being removed-something has to lower as a function of the percentage of the volume of that amount of material, and it takes more energy to lift a cup of water out of a skimmer than 1/2 cup of water

if the amount of protien is the same (and i've yet to see/read/hear of anything contrary to this), then more energy was required by the skimmer to remove that same amount of protien, since in one case it also removed more water, which requires more energy

I seem to not understand how a skimmer skimming wet vs dry uses more energy. It makes no sense.

What do you mean by energy then?

The same amount of power is being used no matter what. Its not like the pump is using more energy one way or the other. Thats like saying a pump that pumps water 10ft is using more energy then one that is pumping water 5 ft. Its simply not true. The pump is using the same amount of power/energy. The water at the end of the 10ft section would come out with less force, but that has nothign to do with what we are talking about.

Maybe I just dont understand what your getting at.

Tammy3770

09/28/2005, 01:20 PM

I heard that salinaty plays a role in how much your skimmer skims, is that true?
and should that be concitered in this discussion or not?
sorry I have no Idea and I'm trying to learn.

Tammy3770

09/28/2005, 01:26 PM

Originally posted by vitz
you seem to either miss, or ignore, my point

the issue i'm dealing with is removal of protiens per volume of material removed per x amount of energy used by the skimmer

if more material is being removed-something has to lower as a function of the percentage of the volume of that amount of material, and it takes more energy to lift a cup of water out of a skimmer than 1/2 cup of water

if the amount of protien is the same (and i've yet to see/read/hear of anything contrary to this), then more energy was required by the skimmer to remove that same amount of protien, since in one case it also removed more water, which requires more energy

i think he means that youre not useing the full potential of your skimmer bubbles if you skim wet.
I dont think he means wattage fo the pump.

like when skimming wet the bubbles push water and dirt insted of just dirt and if you set it correctally you'll just get dirt,
Maybe there is a point (setting) where you can get maximum dirtand thus maximum efficancy of the skimmer bubbles?

is that what you mean vitz?

for the record I skim wet.
as long as there is stuff comming out of the skimmer I'm happy

and yes we all know i cant spell but there is no spell check button.

Agu

09/28/2005, 01:39 PM

it takes more energy to lift a cup of water out of a skimmer than 1/2 cup of water

Granted, but my skimmer adjusts by raising/lowering the collection cup so additional lifting is offset by less height to lift.

I skim wet because I want waste in the collection cup, not rotting in the neck of the skimmer. Dry skimming leaves substantially greater deposits of waste in the neck of a skimmer and less in the collection cup ime. Until it's actually in the cup or the neck of the skimmer is cleaned the waste is still technically in your tank.

I can't imagine leaving waste in contact with your tank water would be a good thing...........

jmo,

Ereefic

09/28/2005, 01:48 PM

How is what is in the neck of the skimmer still in contact with tank water?

vitz

09/28/2005, 02:22 PM

i really don't know how to explain my point any better than i already have, other than to pose it as a question:

if i have a pump removing 1 cup of waste water w/5 gm of actual waste in it, and another pump removing the same amount of waste with 1/2 that amount of waste water, which is running more efficiently?

hint: they CANNOT be equal ;)

vitz

09/28/2005, 02:25 PM

Originally posted by Agu
Granted, but my skimmer adjusts by raising/lowering the collection cup so additional lifting is offset by less height to lift.

I skim wet because I want waste in the collection cup, not rotting in the neck of the skimmer. Dry skimming leaves substantially greater deposits of waste in the neck of a skimmer and less in the collection cup ime. Until it's actually in the cup or the neck of the skimmer is cleaned the waste is still technically in your tank.

I can't imagine leaving waste in contact with your tank water would be a good thing...........

jmo,

"Until it's actually in the cup or the neck of the skimmer is cleaned the waste is still technically in your tank. "

heh says you, and you have no data to back that impression :P

mebbe yes, mebbe no ;)

mebbe the bubbles continually pushing against the 'sludge' keep it from 'reacting' further w/the water?

sellout007

09/28/2005, 02:32 PM

Originally posted by vitz
i really don't know how to explain my point any better than i already have, other than to pose it as a question:

if i have a pump removing 1 cup of waste water w/5 gm of actual waste in it, and another pump removing the same amount of waste with 1/2 that amount of waste water, which is running more efficiently?

hint: they CANNOT be equal ;)

Ok I already addressed this.

If you are getting 1 cup of waste w/5gm of actual waste and it takes you a week to collect that. And I get 1 cup of waste which has 2.5gm of waste every 3 days.

The are equally efficent. Get it? They are pulling the same amount of waste, in the same amount of time. Just skimmming wet, you get more water in there, and you also get the addd bonus of taking out large particles of waste you dont get when skimming dry.

Your not taking into consideration the time alotted to get your 5gm of waste.

photobarry

09/28/2005, 02:40 PM

Originally posted by vitz
"Until it's actually in the cup or the neck of the skimmer is cleaned the waste is still technically in your tank. "

heh says you, and you have no data to back that impression :P

mebbe yes, mebbe no ;)

mebbe the bubbles continually pushing against the 'sludge' keep it from 'reacting' further w/the water?

What about when you feed the tank something like Mysis shrimp that effectively shuts down the skimmer? Then the foam level lowers and you might have a bunch of that sludge slowly drain back into the skimmer.

Why the interest in skimmer efficiency? Compared with tank lighting and all the other water flow devices, running your skimmer wet or dry will have an insignificant impact on total tank energy usage.

Doesn't it take several hours or longer for a skimmer setup for dry skimming to actually start skimming after being cleaned? (And the accumulation of gunk on the skimmer neck reduces skimmate production as well.) Skimmers setup for wet skimming start working immediately and don't have nearly as much down time as one skimming dry. (I would add this to the efficiency equation.)

Tammy3770

09/28/2005, 03:40 PM

Originally posted by sellout007
Ok I already addressed this.

If you are getting 1 cup of waste w/5gm of actual waste and it takes you a week to collect that. And I get 1 cup of waste which has 2.5gm of waste every 3 days.

The are equally efficent. Get it? They are pulling the same amount of waste, in the same amount of time. Just skimmming wet, you get more water in there, and you also get the addd bonus of taking out large particles of waste you dont get when skimming dry.

Your not taking into consideration the time alotted to get your 5gm of waste.

good point but does it really work like that?
I mean what if by skimming dry you get 5grams of waste for 1 week but skimming wet you get 6 grams in a week?
or the other way around?
I dont have that answer
this is a good topic.

sellout007

09/28/2005, 03:51 PM

Originally posted by Tammy3770
good point but does it really work like that?
I mean what if by skimming dry you get 5grams of waste for 1 week but skimming wet you get 6 grams in a week?
or the other way around?
I dont have that answer
this is a good topic.

Your right, we dont really know the answer of how much is taken out, which is one of vitz's points. But from my experience (short experience) it seems it doesnt matter if you skim wet or dry the skimmer still pulls out the same amount of stuff, with one added bonus in skimming wet you pull out whole pieces of food and more detritus.

I would also tend to argue that by taking out water, no matter what you are getting more waste out. Why? Where is the waste in our tank? In the *water*! What are the reasons behind a water change? To exchange bad water wtih good water.

So not only are you taking out the same amount of waste from bubbles, you are taking out larger particles from skimming wet, and you are taking out water, that contains harmful stuff as well.

Sounds to me like a grand slam. That is unless someone can prove you get out more waste by skimming dry. But I dont see how that could happen.

People like to assume skimming dry takes more out because it *looks* darker and nastier and what not.

Tammy3770

09/28/2005, 06:23 PM

Originally posted by sellout007

People like to assume skimming dry takes more out because it *looks* darker and nastier and what not.

they could be right....
the world may never know

sellout007

09/28/2005, 06:40 PM

Originally posted by Tammy3770

the world may never know

What? How many licks it takes to get to the center of a tootsie roll pop? :D

HippieSmell

09/28/2005, 06:48 PM

Why don't you skim wet for a week and dry for a week, collect all the skimmate, dry it, and weigh it? You would need a good scale, but if it was a significant difference you might be able to visually do it.

photobarry

09/28/2005, 06:51 PM

Originally posted by HippieSmell
Why don't you skim wet for a week and dry for a week, collect all the skimmate, dry it, and weigh it? You would need a good scale, but if it was a significant difference you might be able to visually do it.

You would get a false reading with the wet skimmate since there would be a lot of salt in it as well.

edit: If you knew the volume and salinity of the wet skimmate you could make a SW standard and evap that as well. Then just subtract the difference.

Agu

09/28/2005, 06:54 PM

Posted by Agu

"Until it's actually in the cup or the neck of the skimmer is cleaned the waste is still technically in your tank. "

Posted by Vitz

heh says you, and you have no data to back that impression :P

Water enters my skimmer and exits my skimmer, anything that contacts that water can be returned to the tank. Unless there's a skimmer that doesn't recirculate the water back to the tank it's not an impression, it's an observation.

Tammy3770

09/28/2005, 07:04 PM

Originally posted by photobarry
You would get a false reading with the wet skimmate since there would be a lot of salt in it as well.

edit: If you knew the volume and salinity of the wet skimmate you could make a SW standard and evap that as well. Then just subtract the difference.

you are the lab tech.
could you do that at work and give us a result.
I wouldnt know where to start.

MarineDepot

09/28/2005, 08:37 PM

...

vitz

09/28/2005, 08:43 PM

Originally posted by Agu
Posted by Agu

Posted by Vitz

Water enters my skimmer and exits my skimmer, anything that contacts that water can be returned to the tank. Unless there's a skimmer that doesn't recirculate the water back to the tank it's not an impression, it's an observation.

a purely anecdotal one, with a conclusion that has no proof ;)

you assume that everything that touches water in the skimmer goes back into the tank, yes?

i would postulate that the 'sludge' is not as easily resoluble as you seem to think, though i also have no proof to the contrary

there is almost no statement about skimmers functioning and performance that isn't either anecdotaly based, or guesswork, either way, and anyone who says that one is either better or worse than the other really has no hard data to back up the claim.

vitz

09/28/2005, 08:45 PM

Originally posted by sellout007
Your right, we dont really know the answer of how much is taken out, which is one of vitz's points. But from my experience (short experience) it seems it doesnt matter if you skim wet or dry the skimmer still pulls out the same amount of stuff, with one added bonus in skimming wet you pull out whole pieces of food and more detritus.

I would also tend to argue that by taking out water, no matter what you are getting more waste out. Why? Where is the waste in our tank? In the *water*! What are the reasons behind a water change? To exchange bad water wtih good water.

So not only are you taking out the same amount of waste from bubbles, you are taking out larger particles from skimming wet, and you are taking out water, that contains harmful stuff as well.

Sounds to me like a grand slam. That is unless someone can prove you get out more waste by skimming dry. But I dont see how that could happen.

People like to assume skimming dry takes more out because it *looks* darker and nastier and what not.

the wet skimmer folk assume just as much, for many related reasons-and just because either of us doesn't 'see how it could happen' doesn't mean it does, or doesn't ;)

photobarry

09/28/2005, 08:57 PM

Originally posted by Tammy3770
you are the lab tech.
could you do that at work and give us a result.
I wouldnt know where to start.

I would but I think there might be some objections to putting skimmate in the drying oven. :)

Tennismurph

09/28/2005, 09:09 PM

Originally posted by vitz
has anyone found any hard evidence that wet skimming is in fact more effective than dry skimming ?

Could you test it by collecting wet for a period then dry for the same period of time from the same skimmer then evaporating, weighing and comparing the two to see which method collects more junk? Obviously, this wouldn't distinguish what you were collecting and would sure stink up the place!

photobarry

09/28/2005, 09:13 PM

Originally posted by Tennismurph
Could you test it by collecting wet for a period then dry for the same period of time from the same skimmer then evaporating, weighing and comparing the two to see which method collects more junk? Obviously, this wouldn't distinguish what you were collecting and would sure stink up the place!

Is there an echo in here?

Agu

09/28/2005, 09:23 PM

you assume that everything that touches water in the skimmer goes back into the tank, yes?

Trying to catch me in the double question ehhh ;) .

I don't assume, you know what happens when you assume :lol: .

Even if a small percentage of skimmer sludge returns to the tank that's unnecessary sludge in the tank. Besides, I enjoy adding topoff water to the tank. Lets me drip more kalk.

i would postulate that the 'sludge' is not as easily resoluble as you seem to think, though i also have no proof to the contrary

Nor can I verify or prove false your postulate. However I can verify skimmate actually in a skimmer cup is removed from the system (unless of course one pours it back into the tank). whereas skimmate in the neck of a skimmer is still in contact with aquarium water until physically removed.

Which brings us back to the original question, wet or dry skimmate ? I'd hypothesize it depends on the aquarist. An aquarist who is diligent and cleans the neck of his/her skimmer often will have no better/worse performance from their skimmer than one who gets wet skimmate and does fewer skimmer cleanings. So it all depends on how often one is willing to clean their skimmer. It's an unpleasant task and human nature is to avoid unpleasant tasks, therefore wet skimmate is the best option for most aquarists.

jmo,ime,bni,

WarEagleNR88

09/28/2005, 10:56 PM

Originally posted by Agu
An aquarist who is diligent and cleans the neck of his/her skimmer often will have no better/worse performance from their skimmer than one who gets wet skimmate and does fewer skimmer cleanings. So it all depends on how often one is willing to clean their skimmer. It's an unpleasant task and human nature is to avoid unpleasant tasks, therefore wet skimmate is the best option for most aquarists.
Yes! Back to the lazy aquarist. Exactly what I was thinking Agu as I read this thread. I have no idea either way and like what one person said already, if there's stuff in the cup I'm happy. For me, wet skimmate pours more easily. Plus I'm doing little bitty water changes so salinity will decrease over time. So I add extra salt and water to compensate.

Do the bubbles gather more DOC/DOMs and actual detritus chunks when it's a wet skimmate? How do we actually know the exact qualities of each of those bubbles and how those qualities affect the skimmate production? I'd almost guarantee that it comes down to about the same amount less the salt and other non organic particles in the wet. The depth of the wet vs dry discussion and the experiments involved just shows how far you could take this debate.

What is the percentage of gases in the "air" that is in the skimming chamber? Remember 78/21/1? Would 100% O2 bubbles collect more? Or would 100% N2 bubbles? Maybe 100% CO2 bubbles? What if there's another gas that does it the best? He? Would H2 do anything? I've no idea. Then we start getting into the fact that adding one particular type of bubble increases or decreases the pH resulting in a higher or lower affinity of the bubbles for the collection of these hydrophobic molecules on their surface? Would temperature play into the efficiency of a particular bubble of a particular gas on the molecular level? What about the temperature of the water? Remember the gas laws? Also, how would pressure play into the whole equation? We all live at different elevations. The air bubbles in a skimmer at sea level are not quite as large as the air bubbles would be in a skimmer in the Rockies. Does that come in to play? Do larger bubbles produce more skimmate or less skimmate? If it does, then how can the sea level skimmer producing wet skimmate produce more than a skimmer producing dry skimmate at 8000' MSL?

I think the entire discussion will repeatedly come back to the same conclusion. Skimmate is skimmate. Thicker skimmate collected faster is obviously the best. Dry is maybe too thick, wet is maybe too thin; I have no idea. But this is how to get the best: a powerful churning of a full cylinder of a maximum amount of the proper proportion of gas and water molecules for an optimum amount of time pulling those DOC/DOMs to mechanically deposit outside of the system. And I would almost bet out of all of those variables from above and all of the experiments you could do from my questions paragraph, increasing the mixing contact time between the gas and water molecules will produce the best skimmate hands down. What comes out of the top of the skimmer neck is up to the aquarist--wet or dry? That is the question.