There are manufactured additives that raise and lower pH, but most accomplished do-it-yourselfers will rely on muriatic acid to lower pH and alkalinity and baking soda to increase pH and alkalinity.

P- Alkalinity represents the amount of acid needed to bring the initial pH down to pH 8.2, the point at which the phenolphthalein changes color.

It's the balance of things like chlorine, pH, and alkalinity in a pool that keeps it sterilized. If the water is green, that could mean something is out of wack.

The best way to determine if your pond water pH and alkalinity is too low is to have a water test done. Use a clean drinking water bottle or a jar with a lid on it to collect your sample. If you ...