Watermom...I'm hoping that is what's going on (dust settling). I will have to post test results later but everything looks good in that department except my alkalinity and calcium are high. It's a vinyl pool so I didn't think calcium mattered and I've fought my alkalinity for 3 years to no avail. CANNOT get it below 160 no matter how hard I try. However, I'm not having any trouble with my PH (varies between 7.0 on super low side up to 7.6 usually holding steady around 7.4ish). And yes, my liner has little folds like you where you can tell where the foam underneath is duct taped and that is where the "stuff" is. It is all along there in a perfect straight line.

VinylGuy.......my filter doesn't backwash. It just "bumps and swishes". I will carefully check the grids to check for tears, hadn't thought of that. I also don't know if we have a "multiport valve". We have a connection with a handle that we turn on or off to allow water to flow into the filter. Is that the same thing?

The pool party went great with no evidence of "stuff" settling. The pool is crystal clear. This morning, I went out there to turn the filter on and add chlorine and there was still a little bit of white stuff but not a ton. It seems to be mostly in one spot (across where the return jet pumps the water out so that's why I was wondering if it was a filter problem).

Thanks for the help both of you! I appreciate it!