1 Quart
Spa Sentry is the easiest way to control pH for clear, stable water.  pH is the most critical factor because it changing rapidly when bathers, products or other elements enter the water.
Controls pH for up to two full months.
Introduces a buffering compound, making pH easier to keep in balance.
*Please note: Spa Sentry should never be used in spas with plaster finishes or grouting that contains calcium.