Powerhead Burping

[Zolek]

I have a maxijet 1200 powerhead about 10 inches below the water surface. The venturi tube is NOT attached. About once every 45 seconds or so the powerhead spews out a small burst of bubbles. My question is quite simply, where is the gas coming from? Is the water agitation inside the powerhead separating gas from the water? It started doing this only recently, I have just started fertilizing my live plants though. Is it just excess oxygen coming out of the water inside the powerhead or do I need to be worried?

 

[Colin_T]

it sounds like the pump is picking air up from somewhere in the tank. If it has a prefilter or something attached to it the bubbles might be coming from inside that. If there is lots of fine bubbles in the tank they could be collecting under the pump and being sucked in a spat out again.. Maybe turn the pump off and give it a clean. Then see how it goes.

 

[fourthtimelucky]

Try disconnecting it and rotating it under the water for a while. There might be a pocket of air in the workings. My small filter does this after water changes sometimes, if you don't get it out then the 'burping' can go on for a day or so, which always seemed a bit weird to me given the small amount of air involved.

 

[Zolek]

Its still burping. Is it possible that the movement inside the power head is causing excess oxygen from the plants to separate out into bubbles? I can't see any way gas is getting to the power head.

 

[Colin_T]

you can see the oxygen bubbles coming off the plant leaves. They are fine and usually go straight up to the surface. If you have plants next to the pump it might be picking the bubbles up but it would take a lot of plants to make it burp that frequently.
If the filter is touching the gravel there might be rotting matter under it and the decomposing material is producing the bubbles.
Is there an air operated ornament near the filter? Bubbles could be coming off that and getting sucked up and spat out.

 

[Zolek]

Well I cant see bubbles coming off the plants directly so I guess thats not it. There are no air operated ornaments, and no way I can see any bubbles of any type reaching the power head, its also not touching anything just suspended on the back wall. The bubbles are magically coming out of nowhere for all I can tell. They're totally harmless its just really weird....

 

[rabbut]

There is often a small amount of air trapped in the impeller well of the maxijet range, that can lead to this issue. Take it apart, and re-assemble inder water, with the main part upside down, such that you are placing the impeller into the unit from above. This should fix the problem. There are excelent pices of kit, those maxijets, good choise

Rabbut

 

[Colin_T]

very bizarre. One would think if it was air trapped inside the filter it should have eventually stopped coming out.

 

[Seed]

Could this be due to cavitation?

Or is there possibly a pocket of sorts within the powerhead where O2/etc gas can build up until a large enough bubble forms to be caught within the stream of the powerhead?

 

[Colin_T]

there is a small amount of space in the motor where the impellor lives, but that only holds a small amount of air and that should have come out within a few minutes. If it is still going then air must be coming in from somewhere else.

Not sure about cavitation?