FreshWater Mineral Spa Sanitizer

Every single good hot tub manufacturer buys them from a couple companies that make them,brand them,& ships them in whichever company box,logo,color,etc tub co designed to sell to client.Every spa company has it available & all but one kind of the cylinder types is different in that it's small compared to hot springs grey,Sundance yellow ones. Generic brands are amerse mineral sanitizer both square & cylinders.You usually don't have to put them into the filters. Most have a place next to or on top where you can put the square one. They must be submerged & near filters for best results.