Palintest Alkaphot Photometer Tablets - Total Alkalinity Test Tablets
This is a measure of all the alkaline materials in the pool water. In the pH range found in pool waters, the alkalinity is likely to be present in the form of Sodium Bicarbonate. At the correct level, the pH will not alter rapidly as the water is said to be buffered. If the total alkalinity is below 80 p.p.m. then the water will be insufficiently buffered and if it is above 200 p.p.m it will be excessively buffered. In either case the effect of the addition of chemicals will be difficult to control.