How to Clean a Swimming Pool Filter

Different types of swimming pool filters are available in the market today, such as cartridge filters, diatomaceous earth filters, and sand filters. These filters help maintain pool water quality and also remove debris from pool water.

In this process, they accumulate grease and dirt, which have to be removed on a regular basis. Regular pool maintenance throughout the year, irrespective of the pool type, increases the life of the filters.

✦ When the filter becomes dirty, remove it from the pump-filter assembly and rinse off the debris using a garden hose. Do not use the spray nozzle while rinsing, as it could cause the debris to move further into the filter cartridge.

✦ Make sure the filter is rinsed immediately after removing from the assembly. This is because, drying will result in collection of debris on the filter media, thereby making it even more difficult to remove later.

✦ Once the filter has been rinsed thoroughly, allow it to dry in bright sunshine, as drying under sunshine has algaecidal properties.

✦ After the filter has dried, use a stiff paint brush to remove the loose debris from the filter's fabric.

✦ A bucket with a tight-fitting lid is needed to soak the filters. In the bucket add 1 part of pool chlorinator to 6 parts of water. Soak the filters into the solution and cover with the lid. Microorganisms trapped in the filter's fabric will get destroyed in this time. One could soak them for a day, however, soaking them for 3-5 days yields better results.

✦ Rinse the filters in a bucket of clean water and dunk them quickly in and out of the water. After thoroughly rinsing the filters, allow them to dry under sunlight.

✦ Once dried, use the stiff paint brush to once again brush off the dirt adhering to the filter's fabric.

✦ In another bucket, take 10 parts of water and to it add 1 part of muriatic acid, and soak the filters into this acid solution. The acid solution dissolves the minerals stuck to the filter fabric.

✦ On soaking, bubbles will appear in the bucket. This is the indication that the acid is reacting with the mineral deposits. The stoppage of bubbles implies the dissolution of the mineral deposits.

✦ Rinse the acid-soaked filters with water and keep them from drying. 

✦ The filters are ready to be reused in the swimming pool.

Once the chlorinating and acidifying is done, seal the buckets with the lids. This will prevent the chlorine or acid from evaporating, and the same solution can be reused for several filter cleanings.

Certain amount of sediment will appear in the bucket, however, this does not interfere with the cleaning of filters. While adding chemicals, always remember to add the chemicals to the water, and not water to the chemicals.

DE (Diatomaceous Earth) swimming pool filters prove to be one of the most effective types of swimming pool filters, and can last for almost 25 years if maintained well. These filters comprise filter grids or fingers coated with diatomaceous earth (fine powder made from the fossilized remains of sea organisms called diatoms).

The dirt particles adhere to the edges of the DE particles, thereby filtering the water. The dirt collected on the fingers or grids have to be removed. Most DE filters feature multi-port position options such as 'Backwash', 'Filter', 'Rinse' and 'Closed'. Backwash is required to be carried out during and at the end of every season.

The pump has to be turned off, and the pressure vent must be opened to relieve the system of air pressure. Roll out the hose as well. Next, the multi-port valve of the filter must be turned to 'Backwash' position. Switch on the pump and let the pump run in this position for 5 minutes, until the water runs clear.

This process ensures the flushing of the diatomaceous cake from the filter. Next, turn the multi-port valve to 'Rinse' position, and once again allow the pump to run for 15-20 seconds. Repeat the backwash and rinsing until the sight glass in the multi-port valve is clear. Remember to turn off the power before changing the position of the valve.

Roll the hose back, position the valve on 'Filter' position and turn the power on. If the residue still remains in the filter, then it has to be detached from the pump assembly.

Once detached, the cleaning method mentioned here for the cleansing of cartridge filters can be applied to these DE filters as well. The DE earth material must be replaced 2-3 times a year, so that the filter works at maximum efficiency.

Backwashing a sand filter once every month is essential to get rid of the collected debris. The term backwashing means the reversal of water flow through the filter, so as to flush out the dirt. However, before cleaning the sand filter, it is important to identify if the filter has a multi-port valve or slide valve.

To backwash a sand filter with slide valve, one should turn off the pump water and roll out the backwash hose. Twist the 'T' handle, pull it upwards and unlock the plunger. Turn on the power and allow the pump to run for 5 minutes until the water from the back flush hose runs clear.

Turn off the power and bring the 'T' handle to its original, locked position. The backwash is complete and the power can be turned back on. Roll up the backwash hose.

To backwash a sand filter with a multi-port valve, start by turning off the power. Open the pressure valve in order to relieve the system pressure. Roll up the hose and turn the valve position to 'Backwash'. Turn the power on and run the pump for 5 minutes until the water runs clear.

Turn the power off and turn the vale to 'Rinse' position. Turn the power on and rinse for only 15 seconds. Repeat this process 3-4 times. Once the backwashing is done, turn the valve to 'Filter' position. The pressure valve must be closed and the power should be switched on. The sand bed ought to be replaced after seven years.

The frequency of filter cleaning will depend on the type of filter used. However, the general guideline regarding the appropriate time of filter cleaning is when the water pressure exceeds 10 psi. This is because as the filters get clogged with debris, the back pressure on the filter system rises.

Moreover, the overall flow rate of the swimming pool circulation system drops. Placing safety covers can reduce the amount of debris in the water, thereby increasing the life of the pool filters.