I have a power head that is on top of my lr since there is nothing to hang it by. I have only lr and today I saw a 12 inch bubble on the intake?? I was just wondering what it was.
can it be excessive air got trap inside the powerhead when you put into the tank? so maybe the bubble you see is from the powerhead "attempting" to escape. If so, I would pull up the powerhead inside the water and turn it up side down, agitate a bit to let air escape. It happened to mine before.
Always was my opinion it is caused by static electricity. Charge existing on p/h will dissipate and bubbles will no longer be more attracted to p/h than anything else.