I'm sure this has been asked before, but what is the white coating that I have on my pond liner? Is it dangerous to the fish? Is it the same stuff that grows on the rubber pieces of the fx5? I tried scrubbing it off... it's hard to do, and severely clouds the water. It probably won't be as noticeable in my intex pool when I get it set up, right? ; ) Because I'm sure it'll grow there too.