I test my calcium in my tank and it said it was 920ppm.. So i took my water to 3 different lfs and it tested the same my alk is 9.. i stoped using all additives except dkh buffer and i have been changing 5 gallons of water a week on it for the past month and a half and it still has not changed at all. what do should i do nothing in the tank seams to be affected by it so how do i lower it?