A filter that utilizes a thin coating a diatomaceous earth (DE) over a porous fabric as it filter medium that periodically must be replaced.

The filtering medium of a diatomaceous earth filter composed of microscopic fossil skeletons of the “diatom,” a tiny freshwater marine plankton.

Energy or chemicals to kill undesirable or pathogenic (disease causing ) organisms, and having a measurable residual at a level adequate to make the desired kill.

A reagent and test method that specifically measures bromine and free available and total chlorine; produces a series of colors from pale pink to dark red.