Quote Originally Posted by jmcst25
Nope -- no SWC.

It's been several hours and the bubble seems constant if not worse. I also placed a bag over the vacuum relief valve. It did not suck in the bag -- so the air is from somewhere else.

Also -- when I shut off the panels -- there is no air -- so the air is from the panel section on the roof.

Any suggestions on how to find where air could be pulled in from?
I was just reading about bubbles and troubleshooting for solar when I saw your post. Here's an excerpt from powermat's site that details this issue:

TROUBLESHOOTING Air Bubbles:
You should see a big flush of air when the solar heater starts up in the morning. It should stop after a few minutes. If air is entering the pool inlets constantly after the system has started up then the vacuum breaker is probably opening and allowing air to enter. Go on the roof and listen to it. You will hear air entering the vacuum breaker if it is the source of the air. If its not, then you have a leak on the pool plumbing before the pump or near the top of the solar panels. Check the pump lid seal. The vacuum breaker is mounted to the bottom header of the bank of solar panels to try and keep some pressure on it so it stays closed. One remedy is to just live with some air bubbles. They don’t affect the system performance and in fact help toaerate the water in the pool. Another remedy is to have the pump serviced to increase the flow though the solar heater. Perhaps the filter just needs to be cleaned or backwashed.
Kudos to Ken W. for a great site & wonderful insights!