Lately I've noticed a steady stream of very tiny bubbles comming out of my jets when I run the solar heater. I did a test last weekend where I turned the solar off but kept the pump running and instantly the bubbles disappeared. After a half hour or so, I turned the solar back on and instantly the bubbles appeared. I called the solar guy and he said it could be due to my filter being clogged. The pressure is a little high and I was going to backwash it this weekend anyhow, but I'm just looking for other opinions or a sanity check here.
Is this being caused by a dirty filter or is there something else happening here?
Could it be sucking in air somewhere along the piping and heating pannels on the roof, or would I see water leaking out?