Diatomaceous Earth, which is composed of the skeletons of microscopic sea creatures, is the most effective, but also the most complex. DE filters not only remove the smallest particles (1 to 5 microns) of any filter, they actually sort of “polish” the water as it passes through it.
DE filters work by forcing water through the diatomaceous earth, then through a grid and back to your pool. These upright cylinder tanks have long half-moon, rectangularshaped grids or fingers. A spreader, which is connected to a collector or manifold, separates these grids and holds them in place. Water flows into the tank, passes through the diatomaceous earth, through the filter grids, into the manifold and back into the pool.
Because the diatomaceous earth powder performs the actual filtering in both vertical and spin filters, you should never run water through a DE filter without diatomaceous earth in it for more than 1 1/2 minutes. This can permanently damage the grid.
