How to plumb an automatic water change system!

[Bemmer]

Anthony,
I read in your propagation book about setting up an automatic water changing system. I am finalizing the design of my sump and want to include the water changing drain. The sump will be in two sections. The skimmer section 18"L x 30"W, then three baffles to the return section (24"L x 30W). I am planning on having the baffles at 9" high so the water level in the skimmer will be 9" high, then pour over the baffles to the return. The wate level in the return section will be about 7-8" high using a top-off device. When doing water changes I am planning on changing approx 45 gallons (about 10% of my total water volume). Can you give me some insight into where I should drill the water changing drain (skimmer or return section) and how high up in the tank? The height of the tank is 17". I am guessing there is a math formula or something like that to calculate the distance up the tank to determine the amount of gallons that will be removed...but I was not very good in math.

Thanks for your help.

[Randall_James]

L * W * H /231 will yield your numbers (all in inches and 231 is the number of cu inches in a gallon of liquid)

Each inch of depth in the skimmer section will be 2.3 gallons
45 gallons will require 19" of water depth

Each inch of depth in return section will be 3.1 gallons
45 gallons will require 14" of water depth

So neither will provide adequate volume for a single operation.

I would look at how the detritus settles in the current sump. I would then put my fitting in bottom or as close to as I could the "dirtiest" section. (this is so I could stir up the loose detritus and let it flow out with the effluent.

With this method you will need to do multiple water changes to achieve your goal of 45 gallons.
This would also have only minimal effect on the actual percentage of 10% of your total volume. Otherwise you will have to add drains to the entire sump to drain it.

I have in fact put 1/2 holes low in my sump baffles to allow my single drain to empty the sump with very little effect on how the baffles operate.

[Anthony Calfo]

its rather easy...

you have your evap top off device set wherever you want/need the water level in the sump proper (last and lowest sump compartment).

Set the evap float swithc so that it is very finely sensitive (frequently doses small amounts) but is fed by a VERY slow pump (extreme here... 1/4" airline or icemaker line style stream... mere gallons per day rate of speed)

Then you have your auto water change overflow hole drilled either a) slightly higher than the evap-top off level by say... not more than 1/2", or b) drilled at the same level as the evap top off level but with an adjustable elbow that allows you to change the overflow level (my recommendation)

Thus... with the overflow hole/height being less than half inch over the evap-top off level... you can auto (timer) pump new and slightly cooler seawater (no more than 2F cooler) into the display tank which will displace warmer aged water to the sump and out/over the overflow hole! Automatic water change.

And from a waiting/reserve vat (barrel/buckets... whatever) of new seawater... your auto-timer (digital from Radio Shack, for example) can be programmed to do daily, weekly, etc water changes as you wish! Sit down once and calculate how many gallons per day/week you want to change... and how many gallons per minute the pump you use for make-up will push. Simple math.

Then... after just a little bit of evaporation (after each auto water change that bullrushes the sump and overflow hole) the sump proper resumes normal evap top off operations in wait for next auto-water change, which will again slightly overun the evap top off level by just 1/2" or less

Now you may be wondering... isn't that slight overun (<1/2" over float switch level) adding a little bit of salt to the tank and increasing my salinity slowly over time? Well... theoretically yes. But if you will worry about that, then are you also calculating the similarly lost salt due to salt creep? Heehe... point is, either way its a small amount of salt. And either way, with or without salt added or exported (creep)... you still need to make slight corrections over time to the tank by checking salinity. If its a big deal (large sump)... you can compensate then by making your new seawater used for auto-water changes just slightly less saline.

And voila... automatic water changes!

[Randall_James]

so this could be a constant water change as much as an automatic.. sure wish I had a floor drain..............

[Anthony Calfo]

Yes... and the floor drain is kinda crucial here

[Bemmer]

Now...that's watta'm talk'n 'bout. All the calculations were making me a little crazy.

Sounds like a plan. However, i do not have a floor drain. The water change drain (WCD) will flow into a wall drain (sink drain on other side of wall), I can plumb into that drain pretty easily. It will be lower than the WCD hole. I can make it as low as I need to for the old saltwater to be gravity feed into the wall drain. I was thinking about plumbing in at 2" below the WCD hole. The water will be traveling a distance of about 36" from the WCD hole to the wall drain. How does that sound.

Hoping to order the sump today!!!!!

[Bemmer]

Anthony,
I forgot to ask you, how big should the bulkhead hole be for the WCD? 1 1/2" or 2"

[Anthony Calfo]

your wall drain is fine, my friend... of course, because it is lower than the overflow on the sump.

As for the overflow bulkhead size... only you can determine that. I have no idea what size pump you are using to do the auto-fill... how long the timer will be set for running it... how much water will run through, etc.

That said, bigger is better (2" bulkhead perhaps).

And moreover... chances are the percent of the water changed and speed at which you will be pumping remote new seawater will be slow enough that the single bulkhead of any reasonable size will be enough. But you must above all do your own math here to be sure.

[Bemmer]

Thanks for all your advice.

[Bemmer]

Anthony,
I would like to show you my proposed sump drawings, with the auto water change bulkhead hole and the other return pump holes, as well as an overflow hole. I want to be sure I am not missing anything before I order my acrylic sump. Thanks for your comments.




The left side view of the sump shows the overflow drain in the top back corner.

[Anthony Calfo]

your diagram is fine by the measurements, love.

For the purpose of mentioning to others reading this/archiving... I should point out that the overflow hole as drawn is too high as it appears to be above the skimmer partition wall (which would flood the sump level over it and bypass the baffles).

but indeed as you have stated in the measurements... the skimmer wall is 1" higher than the overflow hole. And it will work fine. Quite fine actually... you are getting almost maximum sump-proper volume in this case.

And you will need to install the evap top off (float) device at or slightly below the bottom of the overflow bulkhead drain.

The extra plugged hole in the sump is a great idea too. Be sure to plug from both sides (threaded) so that you can add plumbing as needed in the future without having to drain the sump.

Latsly... if the bottom image is showing the display tank with a single 2" bulkhead drilled for the overflow... I am worried that will not handle enough water through the sump. In fact... I am sure of it. I don't see you even getting a decent (quiet) 1000pgh through it from the sump loop

[Bemmer]

[QUOTE]Originally posted by Anthony Calfo

For the purpose of mentioning to others reading this/archiving... I should point out that the overflow hole as drawn is too high as it appears to be above the skimmer partition wall (which would flood the sump level over it and bypass the baffles).

but indeed as you have stated in the measurements... the skimmer wall is 1" higher than the overflow hole. And it will work fine. Quite fine actually... you are getting almost maximum sump-proper volume in this case.
[QUOTE]

Anthony,
Sorry, I read this part three times but I was a little confused by the two statements. Your first statement says that the water changing drain (WCD) overflow is too high in comparison to the skimmer partition wall. Is the skimmer partition wall the baffles? That is how I think you mean? Then are you correcting yourself in the second statement, when stating the skimmer wall is higher than the WCD overflow? Maybe it is too late or too early for me to understand.

Originally posted by Anthony Calfo

Latsly... if the bottom image is showing the display tank with a single 2" bulkhead drilled for the overflow... I am worried that will not handle enough water through the sump. In fact... I am sure of it. I don't see you even getting a decent (quiet) 1000pgh through it from the sump loop

Anthony,
I should have been clearer on the labeling for the bottom image. That is actually still a drawing of the sump, not the main tank. I realized after I posted the drawing that I labeled it "tank". The 2" drain at the top of the sump tank on the left side is...well, literally an "overflow" drain specifically to avoid flooding the sump. If for some reason, the check valve from the return pipe were to get stuck open or one of the drilled hole below the 1" seaswirl outlet (my return to tank is through two 1" seaswirls) got blocked, I have a third safety feature. This "overflow" drain will be plumbed directly into the same wall drain as the WCD overflow hole. Hopefully, it will never get used.

The main tank has two 1 1/2" bulkheads at the top back corner of the tank. There is no overflow setup other than the two bulkheads. These bulkheads will drain directly into the skimmer section. One will drain into the ER CS12-2RC skimmer and the other into a Marc Levenson (Melev) bubble tower.


Now, to drain a specific amount of water ie 45 gallons or 10% of my total water volume, do I just add the 45 gallons of NSW at the lower temperature, while the sump drains equal amount out of the WCD overflow hole? Is that how the new versus old saltwater amounts are distributed. Cause, I was getting some confusing info on another post about putting the WCD overflow hole under water about half way between the bottom of the sump and the water level. The only way that makes sense is if I have a shut off/on valve coming off of the WCD overflow drain. Right? Sorry, if that sounds confusing.

[Randall_James]

I think he was just clarifying that the measurments although correct, the image itself is not. Even though correctly labled, it is just "drawn" in the wrong spot.

The hole for your wcd is going to be at or just above your topoff switch if I read his meaning correctly. As you start the water change it will in fact "overfill" the sump slightly. This "overfill" will go out your drain hole. As this occurs, the new slightly cooler water will sink to the bottom of the sump to be returned to display.

[Anthony Calfo]

Randall James has it almost exactly correct and quite clear/concise in answer to your post, Rebecca. Much thanks James!

The only clarification here is that new and slightly cooler seawater is sent to the main display, not the sump. And with mere partial water changes (10, 20% etc) it will sink in the greater volume of the main display and displace aged older water to the sump which will, as Randall states, "overfill". Indeed... overflow the drain as intended. And that drain is to be at or only slightly higher than the float switch that maintains the sump level with evaporation top off as described above.

As far as the chap that said putting the overflow hole halfway between the sump floor and running water level/surface... there is some kinf of misunderstanding or mistake. It's incorrect or not practical if even workable.

[Bemmer]

Excellent!!!! yeah!!!

I will make the drawing change to the WCD hole and submit the sump drawings to the tank manufacturer...Now, if only i could decide on a the sump tank manufacturer.

[Randall_James]

http://www.melevsreef.com/

[Bemmer]

Randall,
Thanks for your input on this thread. I really appreciate you helping me understand what Anthony was trying to convey. It was 4 a.m. when I read his thread earlier this morning.

If only I could get my sump made by Marc Levenson. Marc has helped me out a bunch on the boards as I am putting together my big in-wall tank. Unfortunately, my sump is too big and he lives too far away. It is cost prohibitive for me and shipping issues on his end prevent us from doing business together. He is a terrific guy and I would like nothing more than to purchase my sump from him. Thanks for the suggestion.

[Gundo5000]

Thats awesome!

[robsmith32]

Ok, since mine is similar, and he's finished, i am doing a sump, unfortunately not acrylic. And was going to do a ~5% change twice a week, by putting a bulkhead with valve @ 2" higher than the pump bulkhead, and have a float valve for top off at 12" higher than bottom of that bulkhead making it exactly 10 gallons.
Then in rubbermaid mixing container next to it, refill it once it drains.
Is what you're saying above saying this way is not workable?

[fishguy0226]

maybe I missed something in the design, what is to stop this from overflowing with power outages and then on restart running a pump dry? Sorry if this has already been adressed somewher.

[Anthony Calfo]

good point... and without making the setup exceedingly complex, the really short answer is to have a solenoid on the overflow drain that fails closed.

Thus... when power is on, the WCD hardware (timers, pumps, etc) can operate as intended and the overflow drain will be open (uninterupted power keeps the solenoid on/open).

But if the power goes out... the solenoid kicks off (shuts/closes) and the sump will not lose excess water that was not part of a scheduled WC overflow.

Clear or no?

[fishguy0226]

crystal, thanks, I am just in the process of trying to figure out a new basement sump syst. and am getting ideas. I'm still having trouble with the head pressure issue though and the calc. here I don't believe will work.
thanks

[Kathy55g]

How's this for an idea:
so you have a running sump that keeps the level of water, perhaps, about 1/3 the height of the sump. When the return pump is off, the water level is 2/3 the height of the sump.

How about if you plumb a drain bulkhead just above the 2/3 height of the sump. If you always turn the return pump off before you do a water change, then the water you add to the display drains to the sump and "dirty" surface water drains to the floor drain. You just have to remember to turn the pump back on when the water change is done. Kind of semi-automatic. I am thinking of doing this, so I would like to know what you think of it.

Thanks,
kathy

[Randall_James]

Originally posted by kmleah
How's this for an idea:
so you have a running sump that keeps the level of water, perhaps, about 1/3 the height of the sump. When the return pump is off, the water level is 2/3 the height of the sump.

How about if you plumb a drain bulkhead just above the 2/3 height of the sump. If you always turn the return pump off before you do a water change, then the water you add to the display drains to the sump and "dirty" surface water drains to the floor drain. You just have to remember to turn the pump back on when the water change is done. Kind of semi-automatic. I am thinking of doing this, so I would like to know what you think of it.

Thanks,
kathy

You will have something of a volume issue. As if designed correctly, the sump should only pickup a minor amount of water when everything is shut down. Perhaps a few gallons at best?

Now I suppose if you set this up to kill the pumps every day that the repeated smaller changes would work out well. Only problem there is that your topoff water and your water change water may run into balance issues. 1 gallon of topoff and 2 to 5 gallons water change water a day.

Now you need a timer to kill the topoff and bring on water change water during the same time interval. Starts to sound like a lot of "possible" failure paths..

[Kathy55g]

But top-off float valve is at the 1/3 sump level in the example above. As you kill the return pump the water volume in the sump goes up past the 1/3 sump level, closing off the top-off valve. The water goes up to the 2/3 sump level. Then you start adding water 2 degrees colder to the display tank. The display tank overflows to the sump which raises the water level higher than the 2/3 sump level and down the draining bulkhead which is just above the 2/3 level.

I am making these levels up to give an easy number picture. The real levels will be different, as you say only a couple of gallons difference.

Probably I would not do this every day, but rather weekly.