first of all, a big thank you... been hanging around for a year, and this is the first time I've felt that I needed to post. I've solved dozens of problems from reading the forums, and it's been a huge help. So thanks. On to my current situation... (please bear in mind that I'm a complete novice at taking care of a pool, and what little I know I've learned from this forum)
I'm getting air in my returns. Pretty significant amount. And I know that air in my pump is a bad thing. No bubbles in the pump basket (dealt with that already). I've noticed that when I switch my multiport valve to backwash and let it run for a few minutes, then switch back to filter, the air ceases, for a couple days at least, and then the air is back. But from reading here I've gathered that air in the returns is almost always a suction side problem. I don't understand how the multiport valve could be letting air in, wouldn't it just leak water out since it's under pressure when it's passing through there? If it is the multiport, is it something pressing or can it wait? Also, could the problem be with the pump itself? I've had the pool for one year and don't know any of the pumps history.
I have a 10,000 gallon pool, sand filter. Thanks for any help you can offer, I appreciate it.