Pool Filter Clogged? (Complete Guide With The Best Tips!)

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Why is my Pool Filter Clogged so Often?

Pool pump and filter are the heart and kidneys of your pool circulation system. It is natural to be concerned if you have a problem of pool filter clogged very often. Here is what you need to do.

To prevent the problem of pool filter clogged often, make sure to 

1. Backwash every time the Pressure is 10 psi above normal
2. Vacuum to Waste if the pool has an overload of Algae & Solid Debris
3. Use a Sand Filter Cleaner to break down Oil & Mineral Deposits
4. Clean out the “Mud Balls” once a year

Filtering & Backwashing

The objective of a pool filter is to separate out the solid particles and debris from the water so that your pool can be clear, clean and safe. The pump forces the pool water through a barrier of filter media such as sand or diatomaceous earth (DE) in the pool filter.

Water flows through the pores in the filter media but the larger solid particles get trapped. The pores keep getting smaller. Initially this is a good thing as it increases the effectiveness of the sand filter.

As the amount of debris trapped by the filter increases, the pump has to work harder. The pressure reading keeps rising. When the pressure reading is 10 psi higher than the normal then it is time to backwash.

Backwashing of the sand filter is done to clean up the sand media and expel the trapped dirt & debris to waste. In theory the sand media should be as good as new after a backwash. 

Clumping, Clogging & Mud Balling of Sand

In practice, backwashing will not clear the sand media 100%. The mineral deposits and some microscopic solid particles continue to cling. Sand can also form lumps, partly thanks to algae strands and partly due to oils that enter the pool through the swimmers.

These lumps are hard to break in backwashing. Over time the sand will begin to form clumps and start clogging. This is also known as “Mud Balling”. The pressure from the pool pump is unable to break through the clogged sand during the backwash cycle. 

Why Do I Have to Backwash My Sand Filter So Often?

Do you find that you are backwashing your sand filter more often than before? How often you need to backwash a sand filter, obviously, depends on the quantity of dirt & debris in your pool.

The amount of dirt and other contaminants in the pool can go up:

During Summer Pool Season

The pool gets used more during the peak summer months. Kids have summer breaks, the days are longer and it is hot! The coolest place to be in, without doubt, is the swimming pool. Expect and plan to backwash more often!

After Storms

Rain & Dust storms will dump a lot of dirt, dust & yard debris into the pool. The risk of “algae bloom” also goes up. You will need to shock your pool more often. The filter will also be overloaded with dirt. So, be prepared to backwash more frequently!

In Fall 

You & your family will not be using the pool too much during fall. But now you have dry leaves being blown into your pool. They can be, and should be skimmed out as often as possible. Nonetheless the frequency of backwashing may need to go up!

Why Does My Pool Filter Get Clogged So Quickly?

Does the sand in your pool filter get clogged too often? It could be because of one or more of the following reasons:

Algae

Algae, especially green algae, is slimy gooey stuff. It is best that algae strands should not enter the pool filter. They stick and make the sand particles clump together. 

When you have algae in your pool you must get rid of it by shocking your pool. Once all the algae are dead, use a flocculant to ensure they all sink to the pool floor. Then use a vacuum to get them out of the pool.

Make sure to vacuum with the multiport valve on the waste setting. The algae will bypass the sand filter media.

Oil

Every swimmer contributes some amount of oil to the pool. The oil adheres to the sand particles in the filter. Backwashing the filter will get rid of much of the trapped solid debris, but the oil continues to cling on.

Mineral Deposits

Some of the pool chemicals add minerals such as calcium or phosphate to the pool. The dirt and debris from the pool is trapped in the top six inches of the sand layer. The minerals travel deeper into the sand and get deposited.

Backwashing is unable to dislodge the minerals and the deposits keep building up. 

Algae, oil and mineral deposits are a part of the reason for sand in your filter to clog up, in spite of regular backwashing.

How to Prevent a Pool Sand Filter from Getting Clogged? 

You can prevent or at least reduce the chances of your pool sand filter getting clogged up by:

Backwashing based on the Pressure Reading

Some people like to backwash their sand filters every week. This is not necessary. 

Backwashing should not be based on time. It should be based on the pressure gauge reading.

Backwashing a pool sand filter too often is counter productive. Actually, a sand filter is more effective after it has trapped some amount of dirt & debris. The pores in the sand become smaller and are able to trap solid particles more effectively.

Backwash your pool sand filter when the pressure reading is around 10 psi higher than the normal psi.

Using a Sand Filter Cleaner

Using a Sand Filter Cleaner, once in a while, helps remove oils, minerals and metals that promote clumping and clogging of the sand. 

In The Swim Liquid Sand Pool Filter Cleaner, breaks down the bonds that oils, minerals and metals form with the sand particles.

Add the Cleaner through the skimmer, with the filter valve on the backwash position. After the cleaner is sucked into the filter, shut off the pump and allow the chemical to work overnight. 

Start it up again the next morning on rinse, to flush out dirt, oils and minerals. Use annually to rejuvenate your filter sand, and keep your filter operating at full effect!

Replacing the Top Sand Layer Once a Year

Most of the debris collection and therefore the clumping takes place in the top six inch layer of the sand media. They call it the “glunk” or “mud balls”.

You should open the top cover and physically remove all the “mud balls”, once a year. Refill the sand filter with the same quantity of fresh sand. This will prevent your pool filter from getting clogged!

When it comes to filter clogging sand is still better than filter balls!

Recommended Pool Sand Filters

Best Sand Media

Aqua Quartz pool filter sand does not stain and ensures easy maintenance at a lower cost by filtering out dust, algae, suntan lotion, oil, leaves and insects. This ecologically safe sand does not solidify and will help prevent clogging and channeling. It is inert, odorless, chemical free, 100% natural sand.

FairmountSantrol AquaQuartz-50 Pool Filter 20-Grade Silica Sand 50 Pounds, White

Best Glass Media

HARSCO METALS & MINERALS Filter Glass is made from 100% recycled materials. The glass filter media cuts down on backwash time as well as loss of pool water and chemicals. Improves water clarity by 25% over sand. 

Filters down to 5 microns, unlike sand only 30 microns. Use 20% less media (by weight) than with sand. Environmentally sound and last 3 times longer than sand.

HARSCO METALS & MINERALS Filter Glass

Best Sand Filter

The Hayward Pro Series Sand Filter for in-ground swimming pools will provide you with hassle-free, effective filtration. The weather-proof tank is constructed of a tough, color-fast polymeric material.

Even water distribution over every square inch of sand is ensured by an integral top diffuser, self-cleaning under drain and 360 degree slotted laterals. Advanced full-flow technology reduces energy costs by achieving excellent filtration, so you can run your filter less.

Thorough backwashing allows for crystal-clear water. Filter is complete with tank, 7-way multi-port valve, sight glass and pressure gauge. 7-way Valve Positions: Filter, Waste, Winter, Closed, Backwash, Recirculation, Rinse.

Hayward Pro Series Pool Sand Filter

Thank you very much for reading the post. I do hope you found it informative and helpful.