The filter in your swimming pool captures and removes dirt and debris, hair, dead bugs. It even skims out finer particles like bacteria, sunscreen, and body oils. Over time, the folds in the filter become clogged, which prevents water from flowing through easily and increases pressure within the filter. The higher the pressure, the less water volume your pump is going to be able to move because it's working harder. The harder your pump has to work, the shorter its life will be.

On top of keeping the pool water clean, the filter also makes sure pool chemicals are distributed evenly. Your hard-working filter needs the same attention you give the rest of your pool to help it run longer and more efficiently. This will, in turn, save you money, energy and time.

There are three types of filter systems: D.E. (diatomaceous earth), sand, and cartridge. D.E. filters are the most efficient, as they can trap particles as small as 3-5 microns. To put that in perspective, the smallest the naked eye can see is 35 microns.

Many DIY folks turn to trisodium phosphate (TSP) and muriatic acid to clean their pool filters. Both TSP and muriatic acid are toxic and require you to wear protective rubber gloves, goggles and a mask when cleaning.

Simple Green All-Purpose Cleaner is aggressive on heavy soils and greasy residue, but gentle enough to clean filters without harming the material. The biodegradable* formula won't leave behind harmful residue to circulate into your pool water.

It's best to clean your filter once a month during summer and every other month in the winter (if you're still running your pool).

Directions for Cleaning a Pool Filter:

Although cleaning with Simple Green does not require you to wear gloves, you may want to here so you don't contact whatever your filter may have sucked up.

1. Turn off the pump. Turn off the entire pool pump and filtration system.
2. Release air. Turn the air relief valve (usually located on top of the filter) slowly to release pressure from the filter.
3. Drain filter tank. Attach a backwash hose to the waste or backwash port. Turn the multiport valve to Backwash. Allow the tank to drain until it's empty.
4. Remove the top. Use a wrench or pliers to open up the clamp handle, then take the top of the compartment off. Be careful not to damage the seal gasket, or O-ring, when doing this. Check your owner's manual if you're unsure about this step.
5. Remove the filters. Carefully take the filter unit out of the tank. Then remove the individual filters and lay them flat on some grass.
6. Mix your Simple Green solution. In an empty spray bottle, mix 2 ½ cups of water with ¼ cup of Simple Green All-Purpose Cleaner. If it's been a while since you last cleaned your filters (or if you've never cleaned your filters), you can mix 1 ½ cups of water with 1 ½ cups of Simple Green.
7. Apply solution. Thoroughly coat each filter in your Simple Green solution, making sure to spray between the pleats.
8. Soak. Leave your solution to soak your filters for about 10 minutes.
9. Clean the filter housing. While soaking, use the same Simple Green solution to spray down the inside and outside of the filter housing. Rinse with your garden hose.
10. Scrub cartridge. After 10 minutes of soaking, expect a bit of loose foam on the surface for a short time. Gently scrub any particularly gunky areas with a soft bristle brush, taking care not to tear the filter.
11. Rinse filters. Starting at the top and spraying downward, rinse each filter with a hose.
12. Lubricate the O-ring. Apply a lubricant to keep it in good condition. If it's dry-rotted, cracked, or looks worn out, you should replace it.
13. Replace the cleaned filters. Secure the filter back in its housing, then replace the top and close the clamps.
14. Turn it back on. Turn your system back on and make sure the air relief valve is still open. Keep it open until a steady stream of water sprays from it, then you can close it.
15. Check pressure. Check the system pressure gauge to be sure it's in the normal range. If the PSI is off, you may have replaced the filter incorrectly. Take note of the new pressure so you'll know when it's time to clean the filter again (when the pressure increases by 8-10 PSI).
16. Rinse grass. Spray down the area you were cleaning in just to further dilute the Simple Green in the grass.

Don't worry if you see a small amount of loose suds across the top of your pool for the next day or so – this is safe for swimmers and it will dissipate.