Pollen and Leaves: Keep Your Pool Filter From Clogging

When does pollen hit North Texas pools?

Cedar pollen comes in winter. Texas A&M AgriLife Today says Ashe juniper, often called mountain cedar, typically begins releasing pollen in mid-December, peaks in mid-January and tapers off toward early March. Cold fronts often trigger the release. Wind carries it for miles.

AgriLife’s article is about cedar fever in people, not pools. It does not say how much pollen lands in a pool. It does say juniper is one of the few plants that pollinates in winter. That means a pool owner who closes down for the season may still find fine debris in the water. See pollen season in the glossary.

I did not find a source for oak, ash or elm pollen dates, so I will not give any. Trees drop leaves, seeds and blooms in different seasons, and every yard is different. Our pool calendar lays out the year.

How do pollen and leaves clog a filter?

Fine pollen and leaf bits flow through the skimmer and pump. The basket catches big pieces. The filter catches the fine material. As the filter fills, flow drops and pressure rises. Less flow means less filtering and weaker chemical mixing. Leaves and live oak debris also clog baskets quickly.

Leslie’s lists clogged pump and skimmer baskets as a cause of low pressure. It advises owners to regularly clean strainer baskets and to remove leaves before they clog the system, which it says is especially important in fall.

How do I know the filter needs cleaning?

Use the gauge, not the calendar. Leslie’s gives these triggers:

The baseline is your reading when the filter is clean. Leslie’s says to note the pressure right after you install a new filter. It also says to check the gauge with the pump off. It should read zero. If it does not, the gauge may be faulty. Leslie’s adds that some manufacturers recommend different pressure ranges, so follow your manual. See pressure gauge in the glossary.

How do I clean a cartridge filter?

Leslie’s lists these steps:

1. Turn off the pump and release the air relief valve before you remove the cartridge.
2. Inspect the cartridge for damage.
3. Rinse it with a garden hose and spray nozzle, held at an angle so you do not damage the material. A cartridge cleaning nozzle also works.
4. For stubborn debris, soak the cartridge overnight in a cleaning solution.

A cartridge filter is rinsed by hand. It is not backwashed. A cracked or worn cartridge should be replaced. Chemical cleaners carry safety labels, so follow the directions on the product. A technician can also clean a cartridge or DE filter for you. See the pool filter repair page.

What about sand and DE filters?

A sand filter is cleaned by backwashing. That reverses the flow and sends dirty water to waste. A multiport valve controls it. Check your city’s rules on where backwash water goes. A DE filter uses powder that must be replaced after cleaning. The steps vary by model, so follow the manual.

If pressure stays high after a clean, the media may be worn, the grids may be damaged or the problem may be somewhere else. See our post on high filter pressure and the pool filter buyer’s guide.

What should I do each week in pollen and leaf season?

1. Empty the pump basket and skimmer basket. Check them more often after wind or rain.
2. Skim the surface before debris sinks.
3. Brush walls and steps so pollen does not settle.
4. Read the filter gauge and write down the number.
5. Test chlorine. Organic debris uses it up.
6. Clean the filter when the gauge hits the trigger.

Marina Pool Services’ weekly service covers emptying baskets weekly, backwashing filters as needed, vacuuming if needed to remove leaves or debris, and brushing walls and steps as needed. See the weekly service page.

When is it more than a clogged filter?

These are possible areas, not diagnoses. If you are stuck, call a pro. Marina lists pool filter inspection and service, and filter replacement and installation, on its filter page. Its algae page mentions that algae can get into the filter too. See the algae treatment page.

What should I write in a filter log?

A short log turns the gauge into a trend.

1. Record the clean pressure after each cleaning.
2. Record the pressure each week.
3. Note the date of each cleaning and what you did.
4. Note the weather, such as a cold front or a windy week.
5. Watch for cleanings that come closer together. That can point to heavy debris, worn media or a filter that is too small.

Share the log with your technician. It makes a diagnosis faster.

Next step

If your filter pressure keeps climbing, see the pool filter repair page, then call Marina Pool Services at (817) 896-1120 or use the quote form at /contact.