Air pocket in my U-tube

[johnvu713]

My U-tube has an air pocket that's getting bigger by the day..will this eventually fail and flood my house via water from the sump to main tank?

[fishes2889]

get a small air line tube and stick it up there and suck out the air...........

Steve

[sjm817]

This is normally caused by not enough flow. What do you have for a return pump? Can you increase the flow?

[dodgersfan25]

yeah just gut a small pump to suck out the air

[sjm817]

Sucking the bubble out is a short term fix. To get it working properly long term, you have to ensure no bubble forms to begin with.

[Bebo77]

shake it... thats what i used to do

[silverarrow27]

Definitely need a higher flow pump.

[johnvu713]

how does a weaker flow pump = to air pocket in u-tube?

[aqua_obs]

i put in a air tube fitting on the top of the syphon tube (appogee) where the air started building up, made sure it was well sealed and ran an air tube from there to an air intake on one of my powerheads. That way when air pushed into the syphon it would be sucked out of the top by the suction from the powerhead. It might also be able to auto start, but that is less likely.

[sjm817]

Water flowing over an overflow weir carries bubbles with it. These bubble travel through the U Tube with the flow. If the flow velocity is sufficient, they get carried through the U Tube. If it is too low, they accumulate in the top. You dont need a ton. usually 200 GPH or so will do it. The other thing is, not all overflows are the same, some by design do a better job with this than others.

You should never, ever see any air accumulate. If you do, something is wrong. An airline fitting in the U Tube is not the correct way to fix a problem. the last thing you want to do in a siphon is to add in an air leak.

I've been using a U Tube overflow for ~ 2 years now (Amiracle, now Lifereef) and have never once seen a single bubble accumulate at the top.

http://reefcentral.com/gallery/data/500/71647PICT1489.jpg

[Packdog]

Yup, sjm is right.

If there is an insufficient flow rate(too low) the air is allowed to collect in the "U" tube rather than be carried through.

I use an over-flow with a u-tube and have witnessed the air bubbles collecting in the tube. When adjusting the flow rates through my sump, fuge, and return, as I increase the flow rate , the bubbles push through and when you reach a certain rate it is impossible for them to accumulate.

If increasing your rate isn't possible, due to having a low flow return pump, you could get a smaller diameter u-tube. I think lifereef sells either 1 1/4"(standard) and like 3/4"(??) inch for this reason.

Not sure if increasing the rate is possible, but this is one of several reasons it's nice to have a oversized pump and use a valve to control the return rather than hoping the pump flow rate is exactly right.

Let us know how it goes.