Powerhead Bubble bursts after lights on a few hours

[SteamCarriage]

I'm curious, I have a powerhead in my saltwater aquarium. In the late afternoon I start to get bursts of microfine bubbles from the discharge of the powerhead. The airhose is not connected and in fact the discharge is at least 2" under the water so there's no way its bringing in any air to discharge. In the morning there are no bubbles. Only after the lighting is on and the grasses and algae start to release bubbles from the leaves does the power head start to throw out these bursts or bubbles every 30 seconds of so.

The only thing I can think of is the plants have saturated the water with O2 and the rapid speed of the powerhead impeller is causing cavitation and the resulting bubbles are being discharged.

Thoughts appreciated.

[James77]

You are right....but it is not cavitation.....it is just the bubbles being sucked in and chopped up if it is happening only when the lights are no :). Can you actually see bubble rising up and being sucked in?You may be able to put some type of sponge that may catch the bubbles?...not sure how that would work though

Cavitation occurs when you restrict the inlet of the pump, which creates a drop in pressure which will cause bubbles to form. I have had that and it is a steady stream of bubbles night and day./

[SteamCarriage]

James,

Thanks for the comments. I initially thought that as well. My problem is I've watched the large intake screen on the powerhead and there's very few bubbles from the plants rising into the intake of the powerhead. There's far too many coming out in each burst for them to be the ones the plants are making.

Also, most of the plant ones are rising at an angle right to the water surface due to current flow and the powerhead is in a corner really out of the rising bubble flow.

I've seen hard cavitation as well and this seems like just just at a threshold point or something. Just to be clear, the lights have to be on for 4-5 hours before it starts happening.

[James77]

How q