I use 3MCQ - the only draw-back is is that when I first set-up my tank I was using a magnetic algae scraper and if any sand got in the scraper, it would scratch the glass. &%&&##$!!!
ditto for me on both of those...and that's with 3MCQ, so don't expect the problem to go awayThe sand looks good right after you clean it. I clean my tank and do 50% water changers weekly and %90 of the time my tank looks like crap. Fish **** might as well have a neon sign pointing down on it. If you ever get diatoms, even in small amounts your sand will look bad.