Installing an overflow

[Rijinals]

Do I basically get an overflow box (hang on) the same lph as the return pump in the sump to keep everything balanced? Or should one be less than the other?

I am thinking, overflow box running at 1500lph and the return pump running the same. Is this normal as I do not have any experiance with sumps. Its going on my 350l tank.

Cheers for feedback dudes!

[rustybucket145]

I would say that overflow should be rated higher than return pump. But I use drilled tanks so that may be why I think that way. Never used a hang on before.

Think if a snail or urchin were to by chance crawl across the overflow temp. blocking some of the flow. Then you would have a real deal OVERFLOW!

[Rijinals]

right got you. so what would be the best ratio out to in??

[SaltyDr]

There is going to be a balance that is achieved where the drain will drain what it needs to based on the return. Therefore the drain needs to be able to handle (rated) at least as much as the return. There will be some head loss so calculate that in.

[Rijinals]

So what about 1500lph overflow, and 1200lpf return?

[TekCat]

it would work just fine. though you'd still probably need to throttle down the pump when you're going to tune the system. good luck

[Rijinals]

Has anyone else got an overflow running with a sump? If so what ratio do you use?

[danch]

I aimed for about 500gph return pump (after head loss) with a 600gph overflow. I also bought a ball valve to put in the return line just in case, but I haven't installed it yet.

As long as the overflow can handle all the flow that the pump can send, you'll be OK (barring stoppage in the overflow or drain, of course - there you have to make sure your sump can handle extra and can't source enough to overflow)

The only thing I'd do different putting it in an existing system would be to install the valve from the get-go.

[TekCat]

I've had an HOB overflow on my old 55G tank, it was rated to 600GPH, I had a 500GPH pump, but had to throttle it down,,... it was sucking out water too fast from the sump, before overflow started drain at the same rate.... So, I think I had water moving at 300GPH. Which might not've been a bad idea, to have somewhat overrated overflow in case of emergency.

[Rijinals]

ok got you, cheers dudes for the good advice! much appreciated!

[SaltyDr]

Don't forget the siphon break in the return line!

[Rijinals]

siphon break? is that just a hole in the line?

[a4twenty]

yep :)