Just wanted to clear a few things up after reading a bunch around the site. When I moved in, the pool (16x32 in grd 19200) service told me that the yellow stains (that don't come off when brushed) on the plaster lining was just because the lining was old and needed to be replaced. Reading here, it seems that isn't the case, and that the stain can be determined to be either metal based (using a vit c tab) or organic (using a trichlor tab), right? Also, cloudiness is caused by algae, and cloudiness when brushing is also algae, right? Waiting for my test kit to do a OCLT, but the more I read, the more it is looking like I might need to SLAM. Gonna wait and get my levels right according to the TFPC method after I get my test kit before I do anything. Just wanted to make sure I was understanding a couple of things. Thanks