If you are replacing DE Powder after a backwash, you will not need to add the full amount - generally around 80%. The grids will have retained some of the DE Power after the backwash, and if you add too much, it may end up in the pool. The best way to assess how much DE Power to add is to monitor the pressure gauge.
Diatomaceous Earth (D.E.) Filter
The D.E. needs to be replenished once the filter is turned back on. Every three months the filter should be taken apart, the grids should be hosed off, and visually inspected for any rips or tears that will cause D.E. to blow back into the pool.
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.
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.
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.
Most DE filters include a recommendation for the total amount of DE powder on a fresh filter. However, if you can't find a suggestion from the manufacturer, you can use a simple rule of thumb: For a full clean or new filter, add one pound of DE powder for every 10 square feet of the filter.
DE (Diatomaceous Earth) filters should be cleaned with special products at least once every season. Perform a complete cleaning and inspection yearly. Check the pressure gauge to figure out when it's time to backwash; the more debris is in your filter, the higher the pressure will be.
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).
At initial start up or after a thorough cleaning, the filter will need to be pre-coated with DE. The filter label will state the amount of DE required. Start the pump and once the pump is fully primed, measure the DE using a DE scoop, part # EC10SC.
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.
Knowing When to Replace Grids
Those with a DE filter should be opening up their filter and cleaning the grids every three months or more often. DE filter grids can last for four or five years with proper care.
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.
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.
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).
Grids usually last a long time, up to about 10 years unless they are subjected to extreme conditions for extended periods.
DE Blow-Back: If DE powder is coming into the pool, you may have torn filter grid fabric. Or, you could have a cracked top manifold, or missing air bleeder. The standpipe o-ring could be missing, or the filter valve could be allowing some DE powder to bypass the filter as you add it new.
Normally, for a DE filter, rinsing the grids/fingers off with water is sufficient. If there is stuff that won't come off with just water you can soak them in detergent. Ideally, for that, you want to use TSP (trisodium phosphate), but that is often difficult to find.
DE FILTER CHEMICAL CLEANING SOLUTIONS
Scale can be removed by soaking the Flex Tube Nest Assembly or the DE Grid Assembly in a 20% solution of Water and Muriatic Acid (5:1 ratio). Soak Flex Tubes in a large bucket and DE Grids in a large (clean) trash can for several hours, and then hose off thoroughly.
Close Relief Valve - Close valve when a stream of water shoots out the end of the valve. Add D.E. Powder - Wearing a protective mask that covers your mouth and nose, carefully scoop D.E. into the skimmer closest to the pump and filter. After adding D.E., make sure to close the lid of the skimmer.
Answer: It is not recommended to swim in the pool when DE is present. It is more dangerous in dry form when it is in the air and breathed in. However, people do swallow water when swimming and swallowing DE is always the danger with it.
How Long Do I Have To Wait To Swim After Adding Pool Chemicals? It is recommended to wait at least 20 minutes to an hour after adding water balancing chemicals. You should wait 2-4 hours (or one full cycle through the filter) to swim from the moment you use calcium chloride in your pool.
Chemically, it is safe to swim. You will need circulation in the pool to introduce chlorine...... keeping it sanitary and algae free. Do not turn your pump off for more than 24 hours or so.
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.