Backwashing a sand or DE filter is a simple task. Shut off the pump, set the multiport valve or slide valve handle to the backwash position, roll out the backwash hose and turn the pump on again. Backwash for 3-4 minutes or until the water runs clear, then shut the pump off and return the valve to the filter position.
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.
After a backwash, to get the amount of DE powder, simply take the recommended amount of DE powder for a new filter and multiply it by 0.8, or 80%.
This leaves your pool a cloudy, muddy-looking mess. Luckily however, the powder usually sinks to the bottom of the pool. The only way to remove the earth from your pool is to vacuum the pool with the filter release valve open. This will allow the earth to flush from the filter.
Adding too much DE to your pool may cause multiple negative results. These ramifications include a clogged skimmer, turning the pool cloudy, reducing the circulatory pressure in the pool and putting too much work on your pump that may result in eventually breaking the pump.
Unlike other filtration systems, cartridge filters don't require backwashing, which means homeowners don't waste the water and extra energy involved in backwashing. The small size of cartridge filters allows them to be run on smaller pumps because they can run with a lower flow rate pump, which saves energy.
As a rule of thumb, regardless of if you have a sand filter or DE filter, you should backwash your pool about once a week during swimming season. The optimal time is right after you vacuum the pool. If your pool has had a lot more use than normal, it may be necessary to backwash twice a week.
The most common reasons why a cartridge, sand, or DE filter's pressure rises quickly, even after cleaning or backwashing, is a clogged or blocked filter, algae or old filter elements. If any of these things are wrong, the pressure can rise rapidly in minutes, hours or days.
As a general rule, you should be backwashing your pool about once a week or in conjugation with your scheduled maintenance. Another industry standard is to backwash when your filter's pressure gauge reads 8-10 PSI (pounds per square inch) over the starting level or “clean” pressure.
After backwashing, new DE must be added to the filter. Add the entire amount of DE the filter recommends. If you see DE returning to the pool, vacuum it to waste, after it settles. The next time you backwash and recoat, decrease the amount by 1 pound.
Open the air bleeder assembly on your filter and turn pump on. Watch the pressure gauge for spikes. After the hose fills with water, backwash your sand filter for 2 - 3 minutes, or until water runs clear.
Cartridges for pools do not filter as finely as diatomaceous earth, which can go down to 1- to 6 microns.
The size of your pool, the efficiency of your pump and filter, and how dirty your pool is are just some of the factors you need to consider. Nevertheless, most pool cleaning professionals would advise against running a pool pump for more than 8 hours a day.
Backwashing is a fairly simple process. Simply turn off the pool pump, set the multiport valve handle to “backwash”, let it run for two minutes (or until the glass viewport on the filter is clear). Turn off the pump, set the multiport valve handle to rinse and let it run for about a minute or two.
The pool filter pressure should be steady, operating in a range of +/- 10 psi. When it's outside this range, very low or very high, then you know that something's wrong. Some gauges allow you to set the clean and dirty range, or you can write it on the filter tank with a marker.
Diatomaceous earth (DE) filters use a powder that attaches itself onto a filter grid inside the filter. If the filter is damaged, the DE powder can pass through the filter and back out the return jet. In turn, your pool turns cloudy and looks muddy – not exactly inviting for a quick dip!
Grids usually last a long time, up to about 10 years unless they are subjected to extreme conditions for extended periods.