There are three main types of pool filters: Sand filters, DE filters, and cartridge filters. In general, a sand filter lasts longest between cleanings and is easiest to maintain. A sand filter usually only needs to be cleaned every 5 years or so. A DE filter requires cleaning at least once annually.
Most sand filters should be back-washed after building up 5–10 PSI of pressure, usually about every one to four weeks. If you have a painted pool, you should remove and replace the sand once a year. Otherwise, replace the sand and check the filter every four to five years.
Sand filters should be cleaned at least once per season, preferably in the fall before closing. You must clean your sand filter after encountering bouts of algae.
Dirty Sand Filter
If the filter is dirty or greasy, then don't be surprised if it takes on the appearance of sandy lard. When this happens, the water doesn't flow through the sand filter media. Instead, it's forced to create a channel down the side of the filter and then returns back to the pool.
Low flow = poor circulation which will lead to algae in the pool. Bottom line, the filter must be backwashed on a regular basis to ensure that your pool water is clear. "When do we need to backwash?" - It is recommended to backwash your filter once every 4-6 weeks of regular use.
At their very best, sand filters only filter down to around 20 microns. Anything finer than that isn't able to be easily filtered and will generally pass right through the filter and back into the pool. As these particles build up they will cause the water to look cloudy.
Changing the pool filter sand is a bit of a pain, especially in the back region, but a bag of pool filter sand costs around R90 at your local Builders Warehouse, and you should only need two bags for most pool filters.
Too much sand and your filter will likely not run correctly or may break when reassembling. Too little sand and you will have cloudy water no matter how much your filter runs.
When do I need to replace my sand? On average, sand should be replaced every 3-5 years. This may be longer if the pool stays clear, or shorter, if the filter runs all the time. The jagged edges of the sand wear down and become smooth as the sand ages.
Your sand filter can last anywhere from 15 years to 25 years or more if cared for and maintained well. Most of the time, you may need to replace parts like valves and gaskets, but you probably won't need to replace the whole system for many years.
Can You Backwash Too Much? If you backwash your pool too much i.e. time duration and/or close frequency then yes you can cause a lot of problems. Some problems that can arise from backwashing your sand pool filter too much are: Loss of water – 500+ litres of water can be lost in each backwashing cycle.
If the filter runs well at 16PSI and then goes up to 25PSI, your pool needs a backwash. “How often should I backwash my sand filter”? Ensure you do it if there's an algae outbreak or after a significant storm. A DE( diatomaceous earth)filter system needs cleaning six or more times each year.
The 'Rinse' setting should be used after backwashing and again run just for a minute or two. On this setting the water is flowing through the filter in the normal direction but once again is being sent to the waste pipe rather than being returned to the pool.
As pool filter sand is considered a hazardous material, you should not simply throw the sand away in your trash can. To properly dispose of the sand, you need to call a disposal expert or take it to a disposal site.
It's a bad idea to use anything in your pool filter except sand specifically processed and sold for that purpose. Play sand simply won't keep your pool as clean as it should be.
You can reuse the filter sand if it's still in good shape. Generally, pool filter sand lasts about 5-7 years before it wears out and needs to be replaced (except for very small filters used on aboveground pools, which usually need new sand much sooner.
Baking soda, also known as sodium bicarbonate is naturally alkaline, with a pH of 8. When you add baking soda to your pool water, you will raise both the pH and the alkalinity, improving stability and clarity. Many commercial pool products for raising alkalinity utilize baking soda as their main active ingredient.
Small amounts of DE can be added to a sand filter after each backwash to improve the filtering. The first time you use DE, you need to figure out how much DE to add to your filter. After the first time, you can simply mix the full amount of DE with water in a bucket and pour that slowly into the skimmer.
Turn the valve to “filter” and remove the pump's strainer lid. Pour sand filter cleaner into the strainer basket and replace the lid. Turn the pump off and leave it off for at least 8 hours. Backwash the filter for 3-5 minutes again to remove dirt, debris, and the cleaner.