Clarkee's Pool Care Guide - Filtration

There are a couple of key essentials for safe, sparkling water, and it all starts with the correct pH level in your pool. The pH affects three areas of swimming pools:

Your pool filter has two functions:
1. It removes debris and oxidized material from the water, returning sparkling water to the pool.
2. It provides currents and circulation within the pool to distribute chemicals and prevent algae from forming in poorly circulated areas.

The water is forced through a filter medium, most commonly sand or cartridge, where the particles are trapped and the filtered water returned to the pool. Filters do not remove algae, nor do they remove bacteria. That’s what chlorine does. Eventually, depending on the size and type of the filter, the filtering medium will need to be cleaned.

In a cartridge filter, this means removing the cartridge and hosing it down to get rid of the debris. However, this alone isn’t enough as much of the dirt is embedded within the cartridge material. Filtrite Cartridge Cleaner is an easy to use product that will clear dirt embedded within the cartridge much more thoroughly than hosing.

A sand filter can be backwashed, which basically means all the dirt is flushed out to waste by simply turning a lever on the filter. Of course, you always lose water whenever you backwash. On average, the backwash cycle lasts for 60 to 90 seconds. After backwashing, put the filter on rinse cycle for a further 10 seconds before returning to filtration. Some sand filters can go a month in between backwashing, but it all depends on the size of the pump and filter and the condition of the pool.

Currents are really important in your pool, that’s why you should run your filter 8 hours per day over summer. Most pools have a ‘dead spot’ somewhere; an area that is poorly circulated such as swim outs, behind ladders etc. Algae will usually grow in these dead spots, even if there is sufficient chlorine in the pool. The current can help ensure chemicals are spread throughout the pool and prevent dead spots from occurring.

Which type of filter is best for you?
A sand filter is probably easier to use. Simply by turning a valve handle the filter cleans itself, making regular maintenance easy. However, you lose water every time the filter is backwashed, which you need to consider.

Additionally, the sand needs to be replaced about every 5 years. A cartridge filter packs a whole lot of filtering area in a compact tank, so you usually get longer filter cycles in between cleaning. And because there’s no backwash valve there’s minimal water loss. However, to clean the cartridge the filter needs to be dismantled and the cartridge removed to be hosed down or soaked in a cartridge cleaning solution, so there’s a little more maintenance involved. But both sand and cartridge filters can deliver sparkling clear water provided water balance is correct and the correct level of sanitiser is present.