How to prevent display tank from overflowing

JustJoan · Oct 5, 2021

I am currently getting my 75 gallon tank ready so that I can move my 50 gallon corals and fish into it. I did all the plumbing and filled it with water to test it. I have a check valve in the line for the return pump, and I marked how much overflow room I need in the sump in case of a power failure. My problem right now- I used my gate valve on my return line to set the water level and to equalize the water coming down from my main tank into my sump and what my return pump is pumping up into my display. I let it run all day, it stayed equal. I went to bed, confident that it would continue to keep the water level equal. When I got up in the morning, my display tank was about to overflow. I have searched the internet, I am having a hard time finding something that will shut my pump off when the water in the display tank gets too high. I was wondering what other people do so they don't have a flood.

piranhaman00 · Oct 5, 2021

JustJoan said:
I am currently getting my 75 gallon tank ready so that I can move my 50 gallon corals and fish into it. I did all the plumbing and filled it with water to test it. I have a check valve in the line for the return pump, and I marked how much overflow room I need in the sump in case of a power failure. My problem right now- I used my gate valve on my return line to set the water level and to equalize the water coming down from my main tank into my sump and what my return pump is pumping up into my display. I let it run all day, it stayed equal. I went to bed, confident that it would continue to keep the water level equal. When I got up in the morning, my display tank was about to overflow. I have searched the internet, I am having a hard time finding something that will shut my pump off when the water in the display tank gets too high. I was wondering what other people do so they don't have a flood.

You need to open the gate valve on the overflow or turn the pump down.

Ditch the check valve , or at least don’t rely on it, they fail often.

Your pump should be rated lower than overflow.

KStatefan · Oct 5, 2021

What type of drain system do you have?

Gtinnel · Oct 5, 2021

If you only have one drain line then you shouldn't have a valve on it. Most systems that have a drain with a gate valve also have an emergency drain as well

keithw283 · Oct 5, 2021

either open up your valve on your drain more or choke off the return valve. If you have both options it's probably better to open up the valve on your drain pipe

Quietman · Oct 5, 2021

Design. The weir height in the display tank and the return section of the sump should be sized so that if the return section gets pumped into the display with no return flow it will not overflow the tank.

I have a pump with a "run dry" shut off (never tested it though).

If you're running one drain (emergency drains are a good thing) the above is very important. Recommend Durso set up for one drain (low flow though and no gate valve - I have had valves clog with snails).

Running two drains (backup/emergency - herbie) you will get level fluctuations as film builds up in the pipes/valves but overnight is excessive, again - design will save you.

You could also go controller route (I do not for level control other than ATO) but I'd worry relying on float valve/switch - again, design is best.

Viking_Reefing · Oct 5, 2021

Wait what? I think you need to provide a picture of the plumbing because I can’t make heads or tails of the explanation above.
Why do you have gate valve on your return line? That should be on the main drain line if you also have an emergency overflow.

JustJoan · Oct 5, 2021

MichaelE said:
Wait what? I think you need to provide a picture of the plumbing because I can’t make heads or tails of the explanation above.
Why do you have gate valve on your return line? That should be on the main drain line if you also have an emergency overflow.

Yes, sorry, the gate valve is on my drain line.