Excellent article!

[cfockler]

I've only been studying and keeping saltwater for about 5 months now so these questions may seem odd.

1) How can your water be "crystal clear" if you also have "reef snow" ? If you've got all the algae and critter in your water column then wouldn't it look just a little clouded? I would think a biodiverse tank SHOULD look a little couded...

2) I'm interested in starting some plankton cultures and am curious to have your opinions regarding refugiums. As I understand it the main point of the refugium is to help the plankton reproduce without predation. So if I culture and feed my own plankton it seems I really wouldn't have a reason to bother with the refugium. I do plan to add reverse lighting (on at night) and macroalgae to my sump, but don't see a need to mess with the hang on refugiums that trickle feed down into the tank. It seems that aquacultures would be much more useful. Am I off base here? Or is there a reason to do both?

3) I read an awesome book about a year ago discussing the Algae Turf Scrubbers (can't remember the name) and the point was raised that centrifulgal pumps may be killing many of the waterborne critters. Where can I find more info on alternative pumps? I believe there is a pump called a "bellow" pump? This sounds like a great alternative to my skimmer.

So much to learn. Thanks for the inspiring article.

Clint Fockler
Columbus, OH

[EricHugo]

Hi Clint:

1. The particulates are indeed floating in the water, but the water itself is is extremely clear. Contrast this with tanks that run heavy mechanical filtration. These tend to break down the particulate material and release component organics, like humic acids, that yellow the water. Also, turbidity can be due to both microscopic algae, bacteria, and other microbes. When you cant see it, and it it dense, it makes the water not so clear. Like when water of two temperatures comes together, or fresh and salt water. Hope that clarifies.

2. 3. get to that in a bit. Off to dinner.

[cfockler]

Hope that clarifies.

Clear as mud! Actually, it does make some sense. I assume my heavy duty skimmer is considered mechanical filtration. I've heard of people going "skimmerless", but haven't read up too much on it yet. I'm all for the "More Biology, Less Technology" approach. It just takes some time to absorb all the information to understand it.

Something else comes to mind, perhaps this would be part of #2...

If I feed cultured micro, macro, and zooplankton to the tank regularly, then wouldn't it be better to let the skimmer keep on skimming? Or will that eventually "yellow the water" as you just described?

[cfockler]

Rereading my post just now...and I'm not so confident that a skimmer IS mechanical filtration as you mean it...

Normally mechanical filtration is a filter (pad, net) of some sort in the water stream to catch particulate matter. I can see where this type of matter would eventually break down and color the water because it is IN the water stream.

A skimmer removes the nutrients dissolved in the the water AND some (A lot? I don't know) of the particulate matter, but it is removed from the water stream. So it doesn't make sense that a skimmer would / could color the water.

The algae scrubber I read about long ago did remain in the flow of water. And I could see that it might result in the breakdown of matter similar to a mechanical filter.

So I guess I'm back to thinking that a skimmer and regular feeding (dosing) of various plankton is going to be hard to beat. Time to go back a read your article again!

Thanks again for your time.

[EricHugo]

Sorry bout the delay...long and busy weekend.

>>



Something else comes to mind, perhaps this would be part of #2...

If I feed cultured micro, macro, and zooplankton to the tank regularly, then wouldn't it be better to let the skimmer keep on skimming? Or will that eventually "yellow the water" as you just described?<<

Live foods are great.

I'm neither for nor against skimming. I choose not to skim, but I like skimmers a lot and have used them, set-up systems with them, and am about to set up most of my lab system with skimming. Its a matter of making sure that enough gets put back in for all that is taken out by them.

>>Rereading my post just now...and I'm not so confident that a skimmer IS mechanical filtration as you mean it... <<

Sure it is, just a different way of doing it and a better way.

>>Normally mechanical filtration is a filter (pad, net) of some sort in the water stream to catch particulate matter. I can see where this type of matter would eventually break down and color the water because it is IN the water stream.

A skimmer removes the nutrients dissolved in the the water AND some (A lot? I don't know) of the particulate matter, but it is removed from the water stream. So it doesn't make sense that a skimmer would / could color the water. <<

right on.

>>The algae scrubber I read about long ago did remain in the flow of water. And I could see that it might result in the breakdown of matter similar to a mechanical filter. <<

I'd suggest Adey and Loveland's Dynamic Aquaria for more info on ATS. Algae removes dissolved nutrients and does trap some particulate material, butnot much is the screen is scraped often. But, the algae on the screen tend to color the water - this is mostly chlorphyll related, though. Carbon clears it right up.

>>So I guess I'm back to thinking that a skimmer and regular feeding (dosing) of various plankton is going to be hard to beat. <<

I'd agree.

>>2) I'm interested in starting some plankton cultures and am curious to have your opinions regarding refugiums. As I understand it the main point of the refugium is to help the plankton reproduce without predation. <<

that's right, though it seems these days many people have lost sight of that and treat refugia as quasi-ATS systems or filters, hoping or thinking that significant nutrient processing occurs there, when in fact you want it to be high nutrient to allow the critters that are supposed to be gorwing there to thrive.

>>So if I culture and feed my own plankton it seems I really wouldn't have a reason to bother with the refugium.<<

Well, you can only culture or grow so many types without taking up a lot of space and time to do it. Refugia allow what's already in the tank to reproduce .

>> I do plan to add reverse lighting (on at night) and macroalgae to my sump, but don't see a need to mess with the hang on refugiums that trickle feed down into the tank. It seems that aquacultures would be much more useful. Am I off base here? Or is there a reason to do both? <<

see above. Both is great. culturing is limited, but very useful if you are going to do it. I doubt you will be culturing polychaete larvae or amphipods or msyids, common components of refugia.

>>3) I read an awesome book about a year ago discussing the Algae Turf Scrubbers (can't remember the name) and the point was raised that centrifulgal pumps may be killing many of the waterborne critters. <<

Dyanamic Aquaria?

Yes, several semi-studies have been done on this...some find significant killing, others not so much. I guess it depends on whether the food source (plankton) is in the wtaer column or associated withbottom structure.

>>Where can I find more info on alternative pumps? I believe there is a pump called a "bellow" pump? This sounds like a great alternative to my skimmer.<<

Not commercially available to my knwoeldge, none are convenient or cheap. I'd suggest, if you are really concerned, using tunze pumps. There are also pumps called disc-flo that are incredible....and also incredibly expensive.

[cfockler]

Originally posted by EricHugo
I'd suggest Adey and Loveland's Dynamic Aquaria for more info on ATS.

That's the one! I read that book (and understood maybe half) about a year ago and it eventually led me to buy and start my own saltwater tank. Before then I was only keeping planted freshwater tanks.

Originally posted by EricHugo
...that's right, though it seems these days many people have lost sight of that and treat refugia as quasi-ATS systems or filters, hoping or thinking that significant nutrient processing occurs there, when in fact you want it to be high nutrient to allow the critters that are supposed to be growing there to thrive.
...
Well, you can only culture or grow so many types without taking up a lot of space and time to do it. Refugia allow what's already in the tank to reproduce .
...
see above. Both is great. culturing is limited, but very useful if you are going to do it. I doubt you will be culturing polychaete larvae or amphipods or msyids, common components of refugia.

You want the refugium to have a higher nutrient level to feed the reproducing critters. Got that. Makes sense. I would guess that you'll need a slow water flow through the refugium to provide this scenario.

And you'll get a wider variety of plankton from the refugium than you can culture. Got that.

Ok, here's the confusion for me then. After reading your enlightening article (and others from Dr. Ron) about the QUANTITIES of food that really need to be provided, I don't see how a small refugium will provide enough food to be significant. And I don't see too many people building huge refugiums *yet*.

When culturing, I can provide much higher nutrient levels to the plankton to boost quality and quantity (right?). When I start culturing masses of plankton (2 or 3 species maybe) and feeding it to my tank, won't that reduce the small (although much more varied) amounts produced by the refugium to an insignificant number? Can a small refugium (5 to 10 gallons) produce enough food to be significant to a moderately stocked 75 gallon tank?

Please don't read this as being argumentative, I'm not trying to debate with you. I have no experience here and am just wrestling with the tradeoffs in my own mind. I've got limited space to work with and am not ready to drill holes in my wall to run lines to the basement...yet

Thanks in advance.

[EricHugo]

Well, you are exactly right. I give a presentation where I talk about that...that a refugium would need to be 100 gallons and the reef tank 10 gallons to be really functional..or something along those lines. That's why refugia ae part of the solution, not THE solution.

[cfockler]

Well, how about that...I guess I AM learning something! Thanks for the info.

It sounds to me like small refugia are a SMALL part of the solution. Seems that many people should be focusing more on plankton cultures and less on refugium setups.

[TS]

Hi, just came along this interesting thread.

I would like to remind Clint that refugia have many more uses than culturing foods. Mine is a hang-on-back style, I have added caulerpa to the refugium because I wanted to grow a good amount of it (to compete with less desirable algae) without cluttering my main tank. It also has a couple of hitchhikers I’ve yet to ID and don’t want to unleash on the peaceful denizens of my tank. Then there’s the big, green, unsightly ebo-jaeger heater sitting in there rather than my main tank. There’s a 200 GPH pump feeding this refugium, improving circulation and gas exchange, as well as a 3-inch deep sand bed (the deepest I could do w/ this model) hopefully for denitrification while also providing a good haven for the fauna in the refugium. From what’s in there, you can glean my point- that there are many uses for a refugium, and planktonic culturing is simply one of them. So, I respectfully disagree with the statement that people are focusing too much on them. I think we’re just now starting to realize how much of an improvement they can offer the overall system.

Eric, one of your comments also brought up a question- you say that many people are using refugia as quasi-ATS systems- very true, indeed. But you point out that these will rob the refugium of nutrients that the fauna need. To the extent that the macro filters the entire tank volume, yes, but won’t there be sufficient nutrient supply coming from the main tank?

Thank you for the enlightening and informative discussion, guys. Hope adding my two cents’ worth hasn’t stepped on any toes.

Travis

[cfockler]

Thanks Travis. Don't worry about the toes...I've learned to wear steel-tipped boots when reading any internet message boards!

I appreciate what you're saying about growing caulerpa, stashing hitchhikers, hiding heaters. My point is that these things are all accomplished with a lighted sump just as well. If a person did not have a sump (maybe no room or maybe it's a small tank), then I agree that a hang on refugium would serve those purposes well.

You might increase circulation to the tank with your 200GPH pump, but if the flow is too high then your pods and such might be swept to the tank too quickly and won't flourish in the refugium. I've read that the flow needs to be real slow through there.

My 75gal tank has (will have...I'm working on it) a 4" sandbed so the amount of sandbed added by a small refugium won't be significant enough to help with chemical filtration.

Since my tank already has a sump, I will be focusing my refugium efforts solely on generating food.

My statement about small refugiums being a small part of the solution was exaggerated, I admit. I was having one of those "AhhHah!" moments. I do plan to incorporate a refugium one day, but I've chosen the path less traveled and will be focusing on culturing first.

But when the time has come, here is the refugium design I'd like to try...http://www.reefcentral.com/vbulletin/showthread.php?s=&threadid=30322&highlight=lagoon

It's going to take some major planning to get that approved by my wife and to keep my 5 year old son from swimming in it!