DIY - Projects & Ideas • Sump Flow Problem/question

[wilder_169]

I’m in process of designing my first sump but am having a problem figuring out how to calculate the flow out of the tank to the sump. Obviously if your return pump is running at 150gph and your only getting 125gph into the sump you’re eventually going to have no water in the sump for your pump or vise versa and you will have too much water. Don’t know if you use a ball valve and just adjust the flow or what. If someone could help me out with this that would be much appreciated.

[CITADELGRAD87]

Typically, the drain line is the limiter. Overflow boxes and through tank bulkheads are going to have a predictable GPH, the pump can be any number less than the return limit, remember, you're only going to be spilling whatever the pump puts in the tank.

There are advertised GPH rates on the boxes, and charts online to figure through tank bulkheads.

Don't forget that you are going to have to factor in head height loss, and many pumps, like Danner Supreme Mag Drives, can only approach their advertised rates if they are hooked to a 1.5 inch return line, which is BIG.

[cseals]

They pretty much self regulate themselves. If your pump overwhelms your overflow box add another siphon tube.

[mel_cp6]

If I remember correctly, you first start with how much turnover you want.

For ex: If your tank is 100g and you want a x10 turnover, then you want a pump that's In the range of 1000gph. (don't forget the head loss).

Now you can start looking at overflow. It must drain greater than what the pump can return to the tank. So a 1200gph overflow should do the trick.

Btw. When choosing overflow, make sure It big enough to handle a complete drain when the pump is turned off. If your sump return chamber is to small, there's a risk of flooding your sump and floor.

[Woodworm]

I ran across this site to figure out your return from the sump.
http://www.reefcentral.com/calc/hlc2.php
I can't find the site I had to figure out flow to the sump but I will keep looking.

[tim_s]

Hi,

Simple Answer:

typically you want the bulkhead to be 1.5 times bigger (2 times larger if you want to go the extra mile) than you pump return, this will insure that for the max amount of water the pump can push per hour will easily be returned to the sump.

Also to note the water should be cycling, i.e. nothing should be preventing flow enough that your pump can drain the chamber faster than water can be processed through the sump, you may want to throttle back the pump by creating a return to relieve pressure.

[lilscoots]

I have a pump that will eventually run a much larger tank but in the meantime I put a split in the return line from the pump to flow directly back into the sump with a ball valve so by adjusting that valve I can get maximum flow into the tank without overfilling it or throttling back the motor.

[tim_s]

you may want to throttle back the pump by creating a return to relieve pressure.

^ Quoting myself

I have a pump that will eventually run a much larger tank but in the meantime I put a split in the return line from the pump to flow directly back into the sump with a ball valve so by adjusting that valve I can get maximum flow into the tank without overfilling it or throttling back the motor.

^ Great way of achieving it -- this is also how I do it. Also remember to read the guide about the inner diameter of the piping from the pump to the tank.

For example my Danner mag drive 9.5 has a NPT of 3/4" but the recommended inner sizing for the return for unrestricted flow is 1 /1/2"