1 could be your magnesium,,, naturally calium and carbonate,which is alk. will bind together.. the magnesium is what is naturally the separator or lack of a better term the thing that makes them not stick lol... ive seen tanks literally look like its snowing... 2 could be its not mixed all the way,,, are you using a powder,,, are you making sure its mixed completely before you use it,,, 3 maybe if 1 and 2 are wrong could be your additives are old.. how old are they?... other than that I would just make sure you are testing and using the correct amount... dose in a high flow area,,, if you can try to dose small amounts through out the day,,, maybe s x amount of ml in the morning,, x amount after work or at lunch... x amout after dinner and or before you go to bed... it will be more stable like that aswell.... or just buy a auto doser.. lol...... I hope I helped,, if I can think of anything else ill let you know