Thanks for the help, I'm thinking of picking up Prestone Driveway Heat and follow Randy's two part and dose calcium only. I saw a few bags at shoprite yesterday hope they're all not gone when I stop by later. Phosphate was always an issue for me. I never checked it before this and I think is also a key factor on why I couldn't keep sps. I'm going through a lot of GFO lately just to get it lower but before I had poor husbandry and my tank suffer for that.