A pool that is used regularly is going to gather some grime and debris, if you don’t have a working filtration system keeping the water in your pool looking pristine. It is especially important to keep your pool properly filtered during the summer when it is being used more often.

Most pools have one of three types of filters.

  1. Sand filter – Passes the water through layers of sand to filter out impurities. Very low maintenance, least effective filtration, needs to be backwashed frequently.
  2. DE (diatomaceous earth) filter – Passes water through a fine layer of DE ( specifically pool DE and not garden DE) and through cloth grids, Most effective filtration, requires backwashing ( monthly as a rule of thumb) and twice a year needs to be taken apart and cleaned.
  3. Cartridge filter – Passes water through paper cartridges, filters almost as well as DE, Requires two or three cleanings a year if properly sized for the pool.

What is Backwashing?

Backwashing a sand or De filter is a process by which the water flow is changed in order to send the dirty or contaminated material out of the filter and to a waste line. This reduces the filter pressure and allows the filter to continue to remove debris.

When a backwash is complete on a sand filter it is ready to return to service.

When backwashing a DE filter be sure to replace the DE that was backwashed out during the backwash. Typically, the amount to add is labeled on the tank and can be added to the pool skimmer once the system is set back to a normal filter position.

Signs You Need to Clean Your Filter

Some people have a hard time figuring out when to clean their filter. Those who want to make sure your pool is as clean as possible and want to ensure optimal operation may want to learn the following signs telling you it’s time to clean your filter:

Water Pressure

The first thing you want to pay attention to is your water pressure. The PSI pressure usually doesn’t change when everything is working fine, but if you read your water pressure and it is higher than normal then it may be time for a backwash or cleaning.

It is a good idea after you clean or backwash a filter to write down the starting filter pressure and know that when the pressure reading is 10psi higher it will be time to service the filter again. Some filters even have a bezel that can be set to indicate the dirty and clean pressure reading. Do keep in mind that if you have a variable speed pool pump you will want to be sure and read the pressure gauge with the pump running at the same speed you set it for originally. Slower speeds equal lower pressure and higher speeds equal higher pressure. This is regardless of how clean or dirty the filter is.

Water Flow

The water flow is going to start to show signs of trouble. You are going to notice a slow flow of water going into your pool. This is most dramatic at water features and spa spillways. Low flow can indicate a dirty filter or other issues. IF the filter pressure is high and the water flow is low then most likely it is time to service that filter.

Water Clarity

As you know, the main purpose of this filter is to help clean your water. If the filter is too dirty, then it is going to have a harder time keeping the water in your pool clean. You are going to start seeing the water in your pool get cloudy, and that is a sign that your filter needs a good deep cleaning.

Hopefully, this information helps you keep your filter and pool in good condition.