Double Overflow And Sump Problem

weluvfish54

New member
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on my new 210 gallon tank, we bought 2 sumps with 2 diff overflows.
weve been trying for 2 days now to get them to level out. (intake and return) one sump fills up and the other drains..
been messing with the valves a thousand times and it wont get it right...
turned off one, do u think their fighting eachother?
any suggestions, anyone else have similar setup?
maybe just get rid of tank and get one with built in overflow. help would be cool!
 
I would get rid of one of the sumps. Thats just a disaster waiting to happen. Run both overflows into the same sump. That will fix the problem.
 
i wouldn't use two sumps, and having a built in overflow isn't going to help anything. if you really want to use both sumps you'd be best off having one drain into the other instead of the tank draining into both.
 
I am doing that now. Simple fix. Drill both sumps, install bulkheads and connect them. They will then act as one sump and level themselves by using the other to dump and take water when necessary. I ran mine this way for a while. Perfect. Be sure to test for power outages.
 
we got it! much playing with it and adjusting the over flow boxes to the exact height was the main problem on why it wasnt working befor...2 40 gallon sumps... one has mud crushed coral and sand and live rock with bio balls to pop the air bubbels...only a few.. protein skimmer phosphate remover and chiller and the other has a filter sock and live rock and crushed coral and soon to be uv steralizer and ozonizer and also both have 300 watt heaters=] tank clears up in a matter of mins and looks great!
 
Unless the two sumps have a common connection between them, you will have problems, even if it is just 1 GPH difference between them. You need to fix this.
 
They are not completely separate systems. They share a common display. The flow in and out of the two sumps will never be exactly the same. One will be higher than the other and eventually overflow.
 
then what do you suggest.
theyve been stable for hours now..i have them marked..
how can they affect when they have same pump same overflow everything equal?
 
The problem is they share a common display. Lets see if I can make an example.

Sump A
Pump A pumps 400 GPH to display.
Overflow drain A drains back 401 GPH to Sump A

Sump B
Pump B pumps 401 GPH to display
Overflow drain B drains 400 GPH to Sump B

This is very close to perfectly matched. You have 801 GPH to the display, 801 GPH drained back. The problem is, sump A is draining back 1 GPH faster than it is pumping in. Sump B is pumping 1 GPH faster than it is draining back. Sump A will eventually overflow. This is because the display overflows and pump outlets are common and the sumps are not.

You may have them matched right now (which is quite a feat), but something will change slightly and that balance will be off.

You need to drill both sumps and connect them with a length of plumbing so the sumps will balance.
 
A quick solution would be to connect them with an improvised u-tube. Get some reasonably large pipe or hose, maybe 3/4", and put one end in each sump. Tuck some airline tubing up into the high point of the hose and suck out the air. The sumps will equalize through this siphon tube just like a HOB overflow works. Like a HOB overflow this would have to be monitored closely to avoid trapped air bubbles and siphon failure.

Drilling the tanks is a better long term solution but this would work for now.
 
i have stuff between both of my sumps such as chiller, ballasts etc. so connecting them is really a last option.
were thinking of double overflow box and have them drain into the seperate sumps.
 
Same problem. You still have the problem of exactly matching the drain GPH to the sumps with the pumps output GPH.
 
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