Unstabilized tablets

[chem geek]

Cal-Hypo is also a chemical that doesn't bind together well even under pressure when making pucks (unlike Trichlor) which means that they have to add binders/fillers to the Cal-Hypo to help it to stick together to make a tablet. So as these tablets dissolve, they often leave an insoluble residue, especially as the tablets gets smaller and tend to fall apart more quickly.

[CarlD]

There are some that get around Chem Geek's problem by actually encapsulating the Cal-Hypo in plastic, which, when empty, you must discard. I believe PoolLife may still make them but HTH only makes the tablets, which are horrible. They are supposed to last 5-7 days but I found, in my skimmer, they dissolved in less than 12 hours, and into a skimmer clogging wet cement. I will NEVER use them again.