They are calcium hypochlorite tabs that will add calcium to your pool water. Also, cal-hypo typically can not be manufactured as tablets without a special binder material. It usually leaves a very sticky and gooey residue when all of the cal-hypo dissolves.
You really can use these as a trichlor puck replacement as the left over binder will clog the tubing on an inline feeder. Putting them in a float will leave residue all over your pool.
Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006