Which filter works for you?
Filter choice ( Sand, Diatomaceous earth (DE), and Cartridge ) is generally based on what someone is most comfortable with or what came with the pool. In different parts of the country, some are more prevalent than others. Cartridge filtration in states where water is scarce or expensive (Arizona and California), Sand in the Midwest and D.E in commercial settings and the North East. All filters need to be cleaned/back-washed when the filter pressure is 10 Psi over their clean start pressure
Each has Pros and Cons:
At the fundamental level, sand filters are the simplest to maintain because cleaning them requires only turning a backwash valve. The sand lasts longer than the media inside other types of filters. Sand filters remove particles down to about 20 microns at which point the filter is dirty and needs to be back washed. Backwashing requires water flow of about 15 gallons /per minute and takes 5-7 minutes or 100 gallons of water. The life of the sand depends on the water quality and the number of body oils that are left behind by swimmers about 3-7 years.
This YouTube video does a good job of showing the individual types of filters!
Diatomaceous earth (DE) returns the clearest water because those fossilized exoskeletons of tiny diatoms filter out particles as small as 5 microns, effectively “polishing” the water. DE filters also require backwashing and recharging with the DE powder. This can be a messy job and the discharge leaves a dirty sludge behind. These filters require periodic cleaning of the grids (once a season at minimum). DE filters cost more than sand filters. And the cost of the D.E. is on the rise this year due to the cost of drying the raw materials.
Cartridge filters, particularly today’s larger models, have relatively long filter cycles, more square footage of filtration area, and the fact that cleaning a cartridge filter consumes less water than the back-washing process typically required to clean sand and DE filters. Cartridge filter to 10 microns not as good as DE but better than sand. Cleaning a filter cartridge requires a chemical soak and a good rinse. Usually once after startup of the pool in the spring the maybe 2-3 times during the season and again at the closing of the pool. Cartridge filtration cost about the same as DE.
Why Cartridge Filtration over the other two types?
Economy, time savings, and the environment. Backwashing heated, chemically treated water that you have to replace and also pay for seems a waste. In an area where water is scarce and expensive, backwashing may be a costly affair. Back-washing, charging the DE filter and refilling the pool may only take 15 minutes a week but in a month that hour could have been spent in the pool with your kids. Our environment takes a beating every day, adding DE to the soil along with the chemicals in the water adds to that. Cartridges soaked and rinsed do the same but in a much smaller footprint and with less water and frequency. In season the rinsing off of the cartridge takes 15 minutes and only the pool dirt and some residual chemical left on the pleats. The soaking in the cleaning solution for 24 hrs twice a year has the highest impact on your time and wallet. But both sand and DE also require a good soak in cleaning chemicals at least once a year which evens out the cost and time spent on the cartridge cleaning somewhat. For some good information check out Water Quality and Health
The perfect accomplices for your Cartridge Filtration!
There is one more important reason for cartridge filtration, the large surface area that works well at low gallons per minute, perfect for Variable Speed pumps. Combine a Cartridge filter at the low flow from the VS pump, with a Salt Generator and an energy saving Heat pump and you have the ideal swimming pool. Add properly sized plumbing not only will your pool stay crystal clear, it will also cost very little money and effort to operate and maintain.