Understanding Pool Filtration

Your pool filtration system is the most important part of protecting the investment in your pool. The lifespan of your pool can only be as long as your filtration system can keep it clean. There are several different systems to choose from, so understanding how each one works will help with your decision. Here we’ll talk about the benefits and downfalls of the different pool filtration options out there.

Parts of Your Filtration System

Your pool filtration system is made up of a pump and a filter. The pump circulates water by drawing it through an inlet and propelling it at a high velocity to create a vacuum. As air is sucked from the vacuum, the speed of the water changes and creates energy. That energy then pushes the water through the filter. The filter catches debris by straining the water as it passes through.

Parts of Your Pump

  • The impeller is the moving part of your pump that spins the water to create a vacuum.
  • The motor has a shaft attached to the impeller, which powers the spinning blades.
  • Pump housing collects debris from the water through the pump basket and strainer. The air-tight strainer allows air to be exhausted from the vacuum, pushing it through to the filter.

Types of Pool Pumps

  • Single-speed pumps run at one speed and can use a lot of energy. NOTE: Most single-speed pumps are not compliant with California codes.
  • Double-speed pumps operate at both a high and low speed.
  • Variable-speed pumps work at multiple speeds, which can help homeowners save on energy costs.

Types of Filters

Sand Filters

The most traditional type of pool filter is the sand filter. Sand filters use sand to strain debris and organisms from your pool water. These filters can block particles that are 20-40 microns, with one micron equaling 10-100 human hair widths. The filter consists of a hallow tank attached to a PVC pipe. The pipe is extended to the bottom of the tank and the top is attached to lateral pipes that fan out. The tank is 2/3 full with a special Pool Filter Sand, Zeolite, or Filter Glass.

How sand filters work:

Water flows to the tank through the valve and diffuser. Once inside, water is filtered through the sand bed and pushed up the pipes where it is returned to the pool.

When the filter fills with debris, the pressure inside increases, indicating that it needs backwashing. This is done by reversing the direction of water through the filter using a multiport valve. This process should be done with caution, as backwashing can potentially cause other issues for your pool.

What you should know before buying a sand filter:

  1. Constant backwashing can affect the chemistry of your pool water, so you may need to re-balance and refill your pool from time to time.
  2. Sand filters need a valve to operate, so you may have to purchase one if it does not come with your filter.

Pros of Sand Filters:

  • These filters are typically affordable and easy to use.
  • They require little maintenance and are easy to clean.
  • The sand can be changed every five to seven years.

Cons of Sand Filters:

  • Sand filters are the least effective pool filters.
  • Constant backwashing can raise your pool maintenance costs.

Cartridge Filters

These filters can be a great choice if you are looking for something with a simple design that is easy to use. They have pleated cartridges that increase the surface area of the filter. This allows less resistance which makes this filtration system has a higher turnover rate that puts less strain on your pump.

How cartridge filters work:

Water is pumped through the filter membrane where particles and debris are captured and clean water is returned to the pool. There is a gauge that tells you when it’s time to clean the pool and no backwashing is necessary. The cartridges can be cleaned with a hose when the pressure increases ten points.

Pros of Cartridge Filters:

  • These filters are low maintenance and easy to clean.
  • Cartridges are easy to install.
  • They are highly efficient filters, making them use less energy and put less strain on your pump.

Cons of Cartridge Filters:

  • Cartridges have the potential to get clogged and may need to be cleaned more frequently.
  • The price of some cartridge replacements is high.
  • These filters work best at slow rates.

DE Filters

Diatomaceous Earth (DE) filters use fossilized diatoms to filter particles as small as two to five microns from your pool water. They work somewhat similar to how sand filters work, except they use grids and DE powder instead of sand.

How DE filters work:

The DE powder is put inside the pool skimmer which draws water into the filter. This powder coats the fingered filter grids and is fine enough for water to pass through while blocking debris. DE filters can block particles that are five microns and smaller. These filters can be cleaned by backwashing and removing and washing the filter grids.

Pros of DE Filters:

  • DE filters offer the most thorough filtration of your pool water.
  • The filter grids have a long lifespan as long as they are maintained properly.

Cons of DE Filters:

  • Their maintenance process is more costly and complicated than other filtration systems.
  • DE can be a carcinogen if inhaled.
  • A backwash valve is needed to clean these filters.

Pool filtration is a key element in the lifespan and enjoyment of your pool. It is important that you choose a system that works for your energy budget and your individual ability to care for your system. With the right system, you can enjoy sparkling clean pool water all year long.

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