There are several different types of pool filters available . Many above ground swimming pools come with a sand filter, while the more common options for in-ground pools are cartridge or D.E. filters.

No matter what you have, your pools filter should have a pressure gauge on it showing an acceptable range of pressures before you need to proceed with these cleaning steps. You or your contractor would have set the little green and red pointers showing where your actual pressure should fall between. If your pressure pointer is below the green, that means you are loosing pressure somewhere and may have a leak. If it is above the red, then you have too much pressure in the pipes which causes stress on the mechanical equipment and joints in the piping which can lead to failure and leaks.

Backwashing simply means that we are reversing the flow of water through the filter, flushing out the dirt.

Most D.E. filters have a multiport valve with position options like "FILTER", "BACKWASH", and "WASTE/DRAIN" and "CLOSED"

A D.E. filter has filter grids inside the tank. You add the D.E. powder, which is actually microscopic skeletons of Diatoms or Diatomaceous Earth (hence D.E.), to the pools skimmer, it circulates through the pump into the filter and coats these grids. These diatoms act as tiny little sponges abnd trap the dirt as it passes through in the water.

To Backwash a D.E. Filter

Turn the pump off

Open the pressure valve air vent allowing built up air to flow out

Roll out the hose

By pressing on the multi-port valve handle turn from FILTER to BACKWASH

Run for 4-5 minutes or until the water runs out clear

Turn the pump off again

Rotate the multiport valve to the RINSE position and rinse for 10-15 seconds

Repeat the BACKWASH - RINSE a total of 3 times to ensure the filter grids are as clean as possible. BE SURE TO TURN THE PUMP OFF EACH TIME YOU CHANGE THE MULTI-PORT POSITION

Turn the pump off and turn the vlave position to FILTER Make sure you close the air vent on the top of the filter

Turn the pump on

Note the lower pressure

Roll your hose back up

The amount of D.E. you need to add back to your filtration system will depend upon the size and type of filter you have, so you may need to look at your owners manual the first time and make a note for yourself. Once you know how much you will need, slowly pour the powder down the skimmer which is closest to the filter.

The sand bed in a sand filter can last 5-7 years, however you will have to periodically backwash the filter (usually about once a month) to rid it of debris.

Sand filters have either a multi-port valve like the D.E. filter or a slide valve. If yours has the multi-port valve, follow the instructions as noted for backwashing the D.E. filter above.

To backwash a sand filter with a slide valve

Turn off the pump

Unravel the hose

Twist the T handle and pull it up a few inches to unlock the plunger

Run for 4-5 minutes or until the water coming out of the backwash hose runs clear

Turn the pump off

Replace the T Handle by twisting and pushing to lock the plunger in place

Turn the pump back on

Make a note of the lower filter pressure

Typically, if the pressure rises 10 psi from when you know the cartridge is clean, then it

is time to clean you filter. How many times you have to do this per year will depend on many different factors such as: where you live, how many months per year your pool is open, if your pool is enclosed or covered, if it sits under trees, etc.

You will need a high pressure nozzle for your hose-not a power washer. Hose off the large debris from the filter material. It's alright if the filter doesn't come out white, your real goal is to rid it of as much as possible without damaging the material.

Pool supply stores sell a trisodium phosphate cleaner to soak your filter in to get it really clean once a year.