Controlling GPH flow in sump

[steelhead97]

Hello reefers,

I'm a new reefer and have been keeping a 100 gallon tank with canister filters for the most part. I would like to add a sump to the tank and use a hang on overflow to draft the water down to the sump. I will have the skimmer in the sump and then another pump to bring the clean water back into the tank. My question is how do I balance the amount of water coming down into the sump and the return pump?? It would seem I have to get that gph flow combination just right or there will be no water in the sump if the return pump can pump faster then the overflow can bring down into the sump....What would be the best way to approach this? This may be a very obvious answer to some but ive not set up a sump and don't know. Thanks so much.

 

[Twz]

What ever you pump into the DT (display tank)
Should drain back into the sump,
I do not use any valves unless there for cutting of flow for maintenance.

Is this tank already running?

 

[rbursek]

The over flow has a limit on how much water can go thru it, they usually rate them, then you get a return pump at or below that limit. The amont of water then is in balance, the over flow only flows what the pump pumps. I hope that made sense, maybe someone can explain it better.

 

[OneReef]

It does not really matter how fast the water flows down to the sump. The only number that will concern you is your return pump. It does not need to run faster than the water can drain down to the sump or you will drain your sump dry. The water can only drain to the sump as fast as your pump can return it. Alot of folks put a ball valve on the return line to the tank, and adjust it to get it to what works best for them. But as long as you make sure your pump GPH rating is less than the GPH the overflow box is rated for, you are fine. And if your pump is stronger, just close the ball valve on the return line a little if you have the ball valve attached.

 

[DNickell]

All the above is correct. In practical terms, with a once inch hangon overflow line running over the back of my tank and down to my sump my problem has been getting a return pump that will push enough volume to prevent air bubbles from forming over time in the top of the pipe going over the back of the tank.

There probably are pumps out there that could push more water up a line and into the display tank at a faster rate than your overflow can carry it back down, but most I've seen won't present a problem. (Maybe I just haven't found the right pumps!)