There is not a best or worst pool filter. Each filter (and each piece of equipment for that matter) has it’s own benefits. Your equipment should be custom to your pool, environment and situation.
As a pool owner you need to be asking yourself do I want a filter with the best filtration capability or do I want a filter with the least amount of maintenance. Depending on your preference the answer is very different. Here’s a breakdown of each kind of filter and the positives and negatives of each.
DE Filter
A DE filter uses 8 filter grids and diatomaceous earth. DE is a naturally occurring, soft, siliceous sedimentary rock that’s easily crumbled into a fine white to off-white powder and consists of fossilized remains of diatoms, a type of hard-shelled algae. During filtration the DE coats the filter grids and acts as a barrier capturing water contaminants up to 1 micron and allows the filtered water to pass through the grids back into the pool.
Although DE filters have the most efficient filtration process, it can require the most maintenance and be more expensive than other types of filters. If debree happens to passes through your pump basket it can tear the filter grids and cause you to replace them with each grid running anywhere from $19 to $50. In addition, you have to backwash your system every 4-6 weeks to clean the filter out and recharge it with fresh DE. You have to continuously purchase this DE for between $14 to $30 a bag and will last you 2-6 months depending on how much you backwash and how much DE you add each time you recharge.
Cartridge Filter
I would consider a cartidge filter as having the second best filtration process. It’s made out of a mesh like material that is inserted inside the filter body. Water is pushed through the mesh material and debree up to 10-20 microns are filtered. This system requires you to clean each cartridge about every six months by spraying it down with a hose. These cartridges will last you anywhere from 1-5 years and the cost varys depending on the size and durability.
Sand Filter
In a sand filter system water is pushed through a bed of sand and removed through a set of lateral tubes at the bottom. The filter area of a sand filter is equal to the area of the filter itself. For example, a 24” filter will have 3.14 sqft of filter area. Only the top 1” of sand is actually used to filter the water. The principle behind this filter is that water is pushed through the filter sand, somewhat like an espresso machine. Dirty water goes in the top and clean water exits out the bottom.
As the filter sand becomes plugged with debris from the pool, the pressure increases on the filter and the water flow drops. In order to clean the filter, the filter needs to be backwashed every 4-6 weeks to get rid of the waste water. Sand filters have the least effective filtration and can filter debree up to 40 microns. However, they require the least amount of maintenance and the sand can last up to 5 year before needing to be replaced.