How to keep water level consistent in a sump

[ruincccc]

First time installing a sump, I think I understand how it works in principle from what I read online. One thing I’m still trying to get my head around is how to avoid the return pump overwhelming the overflow box or drying the sump? My understanding is as long as the pump is retiring at a lower GPH than the overflow box is rated, things will be fine. For example, even if an overflow box is rated at 3000 GPH, if the pump returns 2000 GPH it will drain 2000 GPH, but will flood if the pumps returns 3500. Is it a correct understanding? How to factor in evaporation? I assume will need to keep an eye on the sump water level and top off as needed?

 

[esoxlucius]

Usually with a sump set up your gravity drain line is wider diameter plumbing than your return pump plumbing.

So as long as you don't get an oversized pump with an astronomical return rate then you'd be good.

Also, the only part of your entire set up where evaporation will affect the water level is in your return pump compartment. Keep a check on this and top up when necessary.

 

[duanes]

This is true. But.....
You must make sure, that all pipes, or siphons (if it's a true siphon overflow box with U-Tubes) are running at full capacity.
Sometimes, if flow is too low,or too slow bubbles will build up in siphon tubes, and break siphon.
I used over flow boxes with siphons for a long time.....

But found them unreliable.
With some, I needed to attach a line, to the venturi port of a powerhead, to help draw water up, and suck air out, like the CPR box below

After a while I learned to drill tanks, which eliminated the use of siphons, and gave me more peace of mind.
You can make a redundant overflow that works as sort of insurance, in case siphon breaks.

I use this even with drilled tanks, in case I lose track of time when refilling, or because I allow rain to change water, and it sometimes overflows my sump.

 

[Backfromthedead]

I think theres a lot of confusing rhetoric that gets thrown around regarding sumps that more often baffles sump novices than helps them.

Start thinking of sumps in terms of pressure. Water pressure in=water pressure out. You want to equalize the water you're draining from the DT with the water you're pumping back in from the sump if you want a quiet and consistently flowing overflow/sump configuration. If your overflow is making noise/slurping air, then your sump pump(s) are not providing enough pressure to the DT. If your drains in the sump are making noise, then there is not enough water pressure on the drains from the DT.

My advice, if youre making lofty goals of several thousand gph turnover, is to oversize everything. Bigger and more drains with properly installed valves to control flow. Overmatch your drains with a more powerful pump. All pumps run more efficiently, with less waste heat, and with better reliability when they are not ran wide open/full power.

You will definitely need at least one emergency drain. With a properly installed emergency drain you will never need to worry about flooding.

 

[Fishman Dave]

Wow, what kind of sumps do you guys all use?
The answer to the question is YES your understanding is correct!
if the overflow box is rated more than the pump you are fine! (As long as it’s not a syphon setup - I am amazed anyone uses these as they are so risky as they can stop for multiple reasons and hey presto, a flood and a burnt out pump.

The ones I’m used to are simple tanks underneath another tank. The top one having a hole drilled in with a pipe sticking out the top and the bottom. The one at the bottom goes into the sump, the one out the top goes up to the full line of the tank (straight up) and then has a mesh on top. But the full line is around 1”-2” from the very fullest level of the tank.
Then when the tank reaches full from the water pumped up from the sump it overflows into the pipe and back down into the sump.
If the return pump fails, then the sump needs to be big enough to take the 1” depth of the water above the pipe only along with any water in it when running normally.
As long as your return pump cannot match the rating of the pipe, you are sorted. If you keep big fish, remove the mesh for extra peace of mind, as long as you don’t to keep floating plants!

ok this is basic setup, and you can use valves, variable flow pumps, weirs, etc. but water going up equals water coming down and the most this can be depends on the size of the pipe.

you can set up automatic top ups like in a toilet cistern in your sump return pump chamber if you really want or you can just keep topping up regularly for any evaporation. Tbh if you do regular water changes you will get to know the running water level and will keep it to that at water change time.

 

[ruincccc]

thanks guys for all the good inputs!

 

[TwoHedWlf]

Wow, what kind of sumps do you guys all use?
The answer to the question is YES your understanding is correct!
if the overflow box is rated more than the pump you are fine! (As long as it’s not a syphon setup - I am amazed anyone uses these as they are so risky as they can stop for multiple reasons and hey presto, a flood and a burnt out pump.

The ones I’m used to are simple tanks underneath another tank. The top one having a hole drilled in with a pipe sticking out the top and the bottom. The one at the bottom goes into the sump, the one out the top goes up to the full line of the tank (straight up) and then has a mesh on top. But the full line is around 1”-2” from the very fullest level of the tank.
Then when the tank reaches full from the water pumped up from the sump it overflows into the pipe and back down into the sump.
If the return pump fails, then the sump needs to be big enough to take the 1” depth of the water above the pipe only along with any water in it when running normally.
As long as your return pump cannot match the rating of the pipe, you are sorted. If you keep big fish, remove the mesh for extra peace of mind, as long as you don’t to keep floating plants!

ok this is basic setup, and you can use valves, variable flow pumps, weirs, etc. but water going up equals water coming down and the most this can be depends on the size of the pipe.

you can set up automatic top ups like in a toilet cistern in your sump return pump chamber if you really want or you can just keep topping up regularly for any evaporation. Tbh if you do regular water changes you will get to know the running water level and will keep it to that at water change time.

Yep, got to agree with this, was basically how it worked in my sump. The larger the chamber the pump is in the slower the water will drop with evaporation. I had a DIY auto topoff, and my tank evaporated a couple liters a day so it would have been a pain manually refilling it.