Sand filters are the second-best filter type you can buy for a swimming pool. It is in the middle between the cartridge and diatomaceous earth filters in price, speed, and water clarity. A sand filter is exactly what it sounds like. A tank that holds sand that water passes through while dirt and particles are stopped by the sand. When the sand gets overloaded with particles the water flow through the sand slows down and the pressure in the tank rises. This is the point where a sand filter needs to be back washed. Backwashing a sand filter means reversing the flow of water through the sand which forces the trapped particles out of the filter and away from the pool. Backwashing a sand filter is easier than backwashing a DE filter and easier than cleaning a cartridge filter.
The price of a sand filter is usually cheaper than a DE filter and more than a cartridge filter. The sand filter is also average as far as the speed at which it cleans the water. A DE filter is much faster than a sand filter but a sand filter is faster than a cartridge filter. The water clarity of a pool with a sand filter is also average. A cartridge filter will remove particles down to 7 microns. A sand filter, 5 microns, and a DE filter 2 microns. This means that the clearest you have ever seen a swimming pool with a sand filter is not the clearest it could be. A diatomaceous earth filter would remove more and smaller particles from the water making it cleaner.
Overall a sand pool filter is at best average. A very simple filter that uses the space between sand particles to trap particles in water. As you can probably tell I don’t like sand or cartridge filters. DE is the filter to have. I just wanted to share a few facts about cartridge filters in the last post and sand filters in this one. The next post will be about DE filters.