This is interesting because the chlorine does not seem to be budging at all (not losing any). I cannot get an accurate chlorine reading. I have the WalMart test and when I test chlorine, it is a dark dark orange color. So I tried last night to dilute it until it turned yellow and it never did. It went straight from orange to clear so I can't tell what the chlorine reading is. As of Monday when my chlorine was 2, I've added a total of 5 3qt. jugs of 6% bleach which would equal almost 4 gallons which SHOULD have raised my chlorine to a total of 26. However, even when I dilute up to 7 times (which if the color was equal at the 5 line would be 35 chlorine) it is still dark orange. So is my chlorine even higher than 35? Yikes I hope not. The stuff had returned yesterday although not as heavy and I brushed it to mix it back up with the chlorine. There was some yellow staining on the walls here and there, but mostly this stuff in my original picture pretty much concentrated to one area of the pool (NOT the part in the most shade). I haven't kept up with the discussions between smallpooldad and waterbear because it is beyond my level of comprehension (LOL), but just wanted to update everyone since you all were kind enough to help me with my problem (even though the verdict is still up in the air as to what the problem actually IS).