There is no way to guarantee your hot tub will never foam up again. The cause of hot tub foam is something called “thickening water”. This could be caused by a number of factors including, too many chemicals in the water, poor quality chemicals, detergents in your clothing causing soap foam, old water that needs to be changed out. Bromine/chlorine at higher levels will cause foaming on occasion as well. iONRx can drastically reduce foaming in a hot tub by significantly lowering the chemicals in the tub.