I tested this expensive product and was dissapointed as it did not live up to the boasts of negating the use of other chemicles. The PH was high, and it foamed continually. This is not the longly awaited panacea for hot tubs and I reverted back to bromine tabs via the Spa frog which never ever kept the tub supplied with enough bromine and I was continually adding granular bromine to augment.