You should backwash your DE pool filter about once a month during pool season. In addition to the regular schedule, you'll want to perform additional backwashing if: You've been running your pool filter for 48 hours straight. This can cause a pressure build-up, even if the filter grids look clean.
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.
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.
Often, excess sand gets into the wrong places when refilling and will sand to come out into the pool or out of the backwash hose. But it should go away after a few runs. In general, you shouldn't be losing sand from your sand filter. Nor should any sand be coming out during backwashing, rinsing or filtering.
Turn the lever to RINSE, start the pump and rinse for about 15-30 seconds. Stop the pump and turn the lever to FILTER. This is the normal operating position. Close the drain outlet valve and start the pump.
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.
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%.
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.
If you do not add enough DE to your filter, then the grids are not totally coated with DE and the dirt that goes into your filter will attach itself right to the fabric on the grids and will not backwash off. This will cause your filter to short cycle (go very short times between backwashing).
Whenever the filter fills up with the dirt/debris it reduces the flow of water to your 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.
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.
Generally speaking, a pressure reading between 10 – 25 psi can be considered normal. Once you have installed a new filter, turn everything on and take a baseline reading. Each time that you change your pool filter take a new baseline reading.
If the pressure gauge continues to read high after you've cleaned the filter, something isn't working right. Something is preventing water from flowing back into the pool after it passes through the pump. Check for any of these problems: The returns or return valves are closed, partially closed, or blocked.
Grids usually last a long time, up to about 10 years unless they are subjected to extreme conditions for extended periods.
A DE Scoop is specially designed to measure DE powder and 1 scoop is equal to 1/2 lb. of DE powder. To determine how many scoops or coffee cans of DE your filter requires take your filter square footage and divide by 5 (this would be after a full cleaning).
Those with DE filters are probably extremely happy with the quality of water that a DE filter creates, but there comes a time when you will need to replace the filter grids. This is usually after 7-10 years of hard work.
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!
When the pump shuts off, air is drawn into the system, which forces DE powder out the main drains or skimmer. After the system comes back on, some of the powder will be sucked back in and part of it may be left in the pool. Replacing the gasket on the pump should cost about $15.
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.
If you do have this option, it is highly recommended that whenever you have algae, you will need to vacuum to waste. This option allows you to vacuum the algae up and send it out through the backwash line, avoiding getting algae into your filter sand.
Drain/Waste: Opting the drain or waste setting will remove pool water without forcing it through the filter. Backwash: This clears out any debris, dirt and other contaminants that may have accumulated on the filter. Closed: if you choose this setting, then the flow of water to the pool and filter will be stopped.
Air Is the Enemy
The most common reason for weak jets is an air leak. An air leak would come from the suction side of the system. This would be the area between the skimmer and the pump. One way to determine if you have an air leak is by looking for air bubbles coming out of the return jets.