Over flow question

[rolikesfish]

Well, I am thinking about getting a CPR CS50 Over flow box for my 40 gallon display tank. It has a 300 GPH flow. I will have a 20 gallon sump. A few questions, how does this overflow box break the siphon in case the pump shuts off? Is this a good overflow box? And my last questions would be how powerful should my sump pump be to pump the water back up about 3.5 to 4 feet of plumbing?

[hoffy02]

the siphon will break when the water level drops in the DT (pump off) and air enters the u pipe.

not sure on the quality

check the flow rates on the manuf site of the pump you want.. they have a graph of head loss per foot.. match the GPH to the overflow, at the height you have.. measure from sump water level.. not bottom of the sump..

[Reverend Reefer]

if u don't have yer tank full yet, i would highly recommend getting your tank side drilled near the top. i have a siphon overflow, its one of the ones that has a hole on top connected to an aqualifter vacuum pump to keep and start siphon during power outtages. to be honest, sleepless nights sometimes and i worry about it when im away.... hasn't failed in 3.5 yrs but still...

anyways, to answer your question, the cpr overflow cs50 is the same as my overflow box, it has that little hole nubby on top where you're supposed to connect an airline to an aqualifter pump, this will restart and keep bubbles out of the overflow. it should be sold together with an aqualifter, either way, they're only around 15 bucks.

[Reverend Reefer]

Originally Posted by rolikesfish

Well, I am thinking about getting a CPR CS50 Over flow box for my 40 gallon display tank. It has a 300 GPH flow. I will have a 20 gallon sump. A few questions, how does this overflow box break the siphon in case the pump shuts off? Is this a good overflow box? And my last questions would be how powerful should my sump pump be to pump the water back up about 3.5 to 4 feet of plumbing?

oh, didn't see your other question. you want to have a good return pump. i have a mag drive and its priced relatively good. what you do is you look up the pump online, and then there's usually something called a chart or something that you can click on. this will show you how powerful the pump will be at different heights, for example, at 4 feet, a model 2 mag drive pump might only pump 250gph, and then at 6 feet it might only pump at 50gph, or something like that. the ones i know of that are supposed to be good are eheim hobby pumps, iwaki, danner mag drive, i dunno what else. maybe little giant? i guess you could use a fountain pump. it all depends on how much flow you want going through your sump, and also how much your overflow can handle, eg., cpr cs50 max=300gph. so you need to get a pump that is rated at most, 300gph given your height of 4 feet. give or take bends in your plumbing and crap getting in your pipes and overflow, whether you want less flow becuz of a refugium or whatever etc. etc. make sense?