Bubbles Out of Return Line
 

I finally got my first sump going and have noticed that from time to time I get bubbles out of my return line.

It is a 90 Aqueon RR with the Aqueon return kit being fed by a mag 95 through 3/4' flex pvc with plenty of water over the pump.

Any suggestions?

What kind of bubbles are they like micro bubbles ? Are you running a skimmer? It could be bubbles from too much flow through the sump or I have seen a poorly glued fitting with the water running past it wasn't leaking but would pull in air. That I see the mag is at 950 gph it could be too much turnover through the sump they recommend usually 3 to 5 times. The thought behind this is the water is flowing too fast for bubbles too settle out and can become turbulent. Do you have a ball valve on the return ?

No skimmer, they are larger bubbles and come out of the return line nozzles from time to time, kind of like air is building up and getting pushed out.

I may have done a poor glue job, but in the terms of plenty of glue plus the requisite priming and twisting of the fitting to set it. If I was drawing air in it would possibly make a hissing or whistling noise or perhaps drip with the pump off; I will try that.

That's 950 at zero head, I am going up 4 feet and through a 90 and ball valve, so whatever that works out to be; I am guessing 6 or 700. I will crack the ball valve and see if a reduced flow solves the problem.

Sounds like you have air being drawn in at a joint or your water level above you return pump is to low and drawing in air from there.

you pump chamber is probably low if not check the aiming of you return lines. often if their aimed high its possible for air bubbles to be introduce to the water column

Are you still getting bubbles ?

I had this happening until all air was purged from my returns ( 3 nozzles total on one line )
Since I've installed a check valve it has stopped as the return no longer drains all the way back to the sump

sorry, I have been busy with work and haven't had a chance and won't until the weekend ....

no vortex and I have 6 plus inches of water over the intake 99.99% confident that I am not drawing air in there; I only added one joint to my pre-existing plumbing. I will block my to outlets for my return and check for a leak.

the entire length is below the water line; the return standpipe 90 did come with the factory drilled anti-siphon hole though, maybe I will look closer at that.

it has been running a solid 10 days now, it should all be purged out.

I will post an update this weekend, thanks all for the ideas.