Anybody on here ever used this stuff, Mark Weiss product and Black Powder. I've been reading a few reviews and i see the only negative comments are made by people who never tried it. I've used it for couple of days, and the only result I see is that it makes my skimmer go crazy. So i'm curious to see if someone uses this kind of stuff here or had past experience. I would like to hear from people that actually tried this stuff.