It will be hard to get FC, TC, CC from the Wal Mart testers. I got my Ben's test yesterday- AWESOME. I've had mustard algea this week as well. I put in Yellow Out and boy did it eat my chlorine. I brush daily and it continued to return in the same spots. It's been about 4 days and it looks as though it's all gone. Don't think you needed to change filter sand. Bleach, bleach, bleach. Mine was at 22.5 FC 0 cc, today 16 FC, 0 cc. You must keep it high for a couple of days. Keep brushing daily. It will work. I've went through about 20 jugs of bleach this week!