Overflow help

nate213

nate213

Member
Last weekend I setup a 29g sump / refugium under my 75g DT. I used a Eshopps PF-1000 overflow box and Quiet One 4000 return pump. The overflow is rated at 900 gph and the return pump is rated at approx 750 gph at 5' head. My problem is that only one of the J-tubes stays primed. I can start a siphon in the 2nd tube, but after about 1-hour it accumulates enough air to loose siphon. The pump seems like it is pulling more than enough flow and it will pump down faster than the overflow will keep up with. The drain lines are dual 1" ID flex hose and the return line is 3/4" ID flex. No elbows or ball valves in either. Should I try a larger pump, or is there something wrong with my overflow setup?
 
geoj

geoj

Active Member
No air must be allowed to enter the U-tube if the siphon is to be maintained. I would check the tube for cracks if there were no clear source of air entering the U-tube.
 
nate213

nate213

Member
No cracks in either of the tubes. The overflow will only keep one going at a time and it doesnt matter which one. I can maintain either of them going, but not both. Hope that makes sense.
 
acrylic51

acrylic51

Active Member
Did you try swapping the "U" tubes....meaning the 1 that always stays running take it out and put the other tube in it's place? It appears water isn't entering the overflow quick enough to me.....might try a larger pump, but might have to throttle it back though.
 
geoj

geoj

Active Member
Yep, it sounds like the pump is a bit small. If the over flow box is siphoned down, then the tube on the high side will lose siphon. I say no harm no foul. Or get a larger morrre
powerrrful
pump...
 
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