I have been trying to get my calcium hardness in the correct range with my TF-100 kit. I have everything in the correct ranges except CH. It started out 120 and I have added 75 pounds of Calcium Chlorate and it has only risen to 150 and the test chart says it should be between 250-400. When I stated it said to add 40 pounds and I ended up adding 45 lbs. only went up to 125 . Tested again it suggested 35 lbs which I didand it went up to 150. Am I doing something wrong?