I had lots of people say we needed this. So I went the cheap way and used a knee high. OMG the stuff that is coming through the filter. Since I started using it, the surface area of my pool is MUCH cleaner. When I take it off to rinse, I am amazed at the layer of gunk. What is that stuff? Could it be "baby algae" or just some sort of organic material? Typically my pool looks very clear and my FC has been holding steady. I was just wondering if this is a precursor to an algae outbreak.