Be very careful...when you make 28% sodium chlorite out of the crystals it is completely different than 28% sodium chlorite solution ie. you cannot go out and buy sodium chlorite solution 28% and think you are getting the same thing. Sodium chlorite crystals are 80% pure. That is why sodium chlorite 28% made from the crystals is different from 28% sodium chlorite solution bought from a pool shop or janitorial supplies.