To answer Marie's question on stains just on steps - the stains show up first (better) on steps because they are white. If left untreated, stains also appear on vinyl, skimmers, and even navigator. How do I raise the calcium hardness without going to pool store? Is it worth a try to get it to maybe 200. Would any of you recommend that before trying more HEDP or just up the amount of HEDP after ascorbic acid. I have been keeping FC low 2.0-3.5, but have started to raise my PH as it has been at 7.0 for nearly a month now trying this treatment. Going to start bucket test tomorrow. Thanks