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View Full Version : how can i test to see where air is entering return pump line?

E-A-G-L-E-S
04/12/2006, 10:25 AM
it comes up to a "T" and the extends 3' each way to a set of 90's and then loc-line....
E-A-G-L-E-S
04/12/2006, 12:24 PM
i put extra glue around the hard pvc joints and duct taped over that....i also checked to see that the clamps on flex hose were tight.......and i STILL have a storm of microbubbles from it? :(
MayoBoy
04/12/2006, 12:31 PM
They would be coming from the suction side - not the return side. If there was a leak on the return side, you'd have a stream of water coming out. Bubbles are from air being sucked in.
E-A-G-L-E-S
04/12/2006, 12:40 PM
o.k. ... so where on the intake side could they be coming from?
sump is drilled well below water level?
mr pink floyd
04/12/2006, 12:46 PM
what size pump, and what size tubing, someitmes if pumps are too strong for the diameter tubing, they can suck the mixture right out of the water, so you get microbubbles.

pvc should be at least an inch, for a large pump id go incha nad a half
E-A-G-L-E-S
04/12/2006, 12:50 PM
well...the bulkhead is 1", then on the outside of the sump there is a barbed hose fitting - 3'4" hose - barbed fitting - gate valve - intake of pump............
....how can i use 1" or 1.5" hose and fittings and then get back to 3/4" for the pump intake?
-GRI 520(1600gph) ... with 4 durso drains feeding sump from 210g.
MayoBoy
04/12/2006, 12:51 PM
The most likely culprit would be any threaded connections. Did you wrap well with teflon tape? Or, as Mr. Pink Floyd said, the suction size could be inadequate and the line could be vortexing.
E-A-G-L-E-S
04/12/2006, 12:52 PM
yup...teflon'd and clamped? i'm missing something??
MayoBoy
04/12/2006, 01:05 PM
3/4" suction is WAY to small for 1600 gph. That's about 27 GPM. My chart doesn't even show what the friction is for 3/4". With 1" line, you're moving about 10 fps.

You need to go minimum 1" from tank to pump and use a 3/4x1 bushing right at the pump
E-A-G-L-E-S
04/12/2006, 05:20 PM
i will try that.....
dippin61
04/12/2006, 07:59 PM
<a href=showthread.php?s=&postid=7164258#post7164258 target=_blank>Originally posted</a> by MayoBoy
The most likely culprit would be any threaded connections. Did you wrap well with teflon tape? Or, as Mr. Pink Floyd said, the suction size could be inadequate and the line could be vortexing.

think its cavitation that occurs from too small of return, or drain lines. and if thats the case, only thing that will help is to up your pipe size.
E-A-G-L-E-S
04/12/2006, 08:12 PM
well...i have 2-3/4" drains AND 2-1" drains, so idon't think thats the problem.....but i'm hoping by replumbing to all 1" on the intake side will help.