Why is the suggested CH in a plaster SWG higher than in a non-SWG plaster pool? Using the TFT test kit, my FC is 6.0; CC .5; TA 60, PH 7.8 (fluctuates a lot) ; CYA 60, but CH is only 250 (used to be 300 but has declined). I would have to dump a lot of Calcium hardness to raise my CH (pool is 40,000 gallons) to 300 and am deciding what to do. I have read that mixing it with water may prevent it clumping together on the bottom, but have also read that it will heat up fast that way. My pool water is 70 degrees and someone on this cite said in cold temperature it is more likely to clump. I guess my initial question is whether it is imperative that I raise my CH from 250 (note that my pool was just built in June so relatively new) and if so, should I just dump it in or mix it first.