Constant water level

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Hi everyone

I am struggling to keep my water at a constant level in my external overflow and sump. The water fluctuate up and down
and can't keep it at one level. I can see the pump is changing the flow from strong to weak and than to strong again.

Is there a any trick involved?

This is my first DIY 500x500x500 tank & sump setup and got a herbie style drain with 1 x 32mm drain with ball valve, 1 x 32mm E/drain & 1 x 25mm return running
a Jebao DCP-2500 pump. The external overflow has skimming teeth.


Thank you
 

RiaanP

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How deep is the down pipe opening under water?
Distance between ball valve and water level in sump first chamber?
 
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I would say your overflow pipe is too big for your return pump, I would put a 32mm to 25mm or even 20mm reducer in. I had the same problem till I made the change, trying to do this with a ball valve never really works out well. I put my reducer as high up as possible.
 

RiaanP

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water should run into "emergency", just a little bit. Less than 10%.

The ball valve should be much lower down. Amount of air that needs to be pushed out eventually between ball valve and bottom exit is a lot. And without gravity pressure it will take a lot of time before you get all the air out.

The pipe ends to deep under water. Same reason as above. The deeper into the water the more pressure you need from within the pipe to push out the air. Mine I shorten to just below water level with a 90 degree bend on it. The bend unit gave me some adjustment capability.

First change the bottom end of the pipe to see the effect. If still not satisfactory, then lower the ball valve.

The excess water inside overflow is a lot. When power goes out, there is a lot of water that still needs to find space in your sump, never-mind the head of water in your display. I would make the outlet inside the overflow higher. So that less water drain.
 
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Thanks RiaanP I will try and fix the valve issue, I have already lifted the return higher found out the hard way.:m04:
I reduce the pipe from 32mm to 25mm like Royden said and the water way better and almost steady, it's still fluctuate but not that much.

Is my pump not to big for the tank?
 

RiaanP

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Is my pump not to big for the tank?
Other way around, Your pump is too small for the return pipe thickness. That is why you need to reduce / restrict it or use valves.

A 50mm diameter pipe can handle a lot more flow under gravity than what your return pipe can deliver, or your overflow box can handle. No restrictions and you will suck in air that will generate that running toilet sounds.

Actually do not go out now and by the biggest return pump. Your overflow with the comb in place will not be able to handle that, or when a bit of something blocks the comb just that little bit. And you could flood your display. What is your water head at the moment. The difference between the actual water surface and the bottom part of the comb?
 

RiaanP

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ok, you do not want that higher.

Higher than that and you can get slow swimming fish like clowns stuck there.
 
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Thanks RiaanP and everybody's input and help. I will try to redesign the pipe layout again and hope it helps because
I am getting frustrated for struggling with the water level.
 

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