Backwashing is the act of cleaning your filter after it’s collected dirt and debris from your pool. It works by sending pool water backwards through your filter and out the waste or drain port.
In this guide, I’ll teach you the steps to successfully backwashing a DE filter, and how often you should be doing this. First, let’s start with how to backwash a DE filter:
How to Backwash a DE Filter in 5 Steps
1. Turn off your filter system and turn your multiport valve to the backwash position or open your backwash gate if you have a push / pull valve.
2. Turn your system back on and run it for about two minutes letting the water flow out of the backwash valve or port. It would be a good idea to use a backwash hose here.
3. After two minutes shut your system off and if you have a multiport valve, turn it to the rinse position and turn your system back on and run it for about a minute. If you have a push / pull valve just run in for about another minute.
4. Now turn your filter system off and turn your multiport back to filter or shut your push / pull valve.
5. Turn your system back on and add fresh DE powder to your skimmer depending on your filter’s instructions.
How to Backwash or Bump a Hayward DE Filter
Turn your filter system off and open the backwash valve. Using the bump handle, bump the filter slowly 15 times. With the backwash valve still open turn your filter system back on and let it run for about two minutes. This will rinse out all of the DE that you shook off the fingers in your DE Filter.
Turn the filter system off and repeat this again to ensure all of the DE has been rinsed out. Bump it slowly 15 times and turn your system back on for about a minute or so.
Shut your filter system off now and replace the cap or close off your backwash valve and now start your filter system back up. Add more fresh DE to your skimmer.
How Much DE to Add After Backwashing
The first thing you need to determine is the square footage of your DE filter. If it’s not listed on the side of the tank, you can easily do a Google search to find out or contact the dealer you bought the filter from.
DE is measured in pounds, so I recommend that you purchase a one-pound DE scoop. However, if you’re in a pinch, you can also use a one-pound empty coffee can. Here is a chart that lists both:
Standard DE Powder Dosage Chart
How Often Should You Backwash a DE Filter?
To determine when it’s time to backwash, you should look at your pressure gauge. The pressure gauge is there to tell you when the pressure inside the tank increases. The more dirt and debris your filter has collected, the more your pressure will go up.
After a fresh backwash, or at the beginning of the season, make a note of what your pressure gauge reads — this will be your normal filter pressure.
If and when your pressure gauges reads 8-10 pounds over the normal running pressure, it means it’s time to backwash. For instance, if your filter is running at 15 PSI normally, and it climbs up to 25 PSI, you should backwash it.
There’s no harm in doing it a bit early, say if you wanted to backwash at 5 pounds over pressure. But I have to point out that the more dirt and debris that’s built up inside your filter, the better it will filter more debris. That’s because the existing debris will help collect finer particles in your water, pretty cool huh?
NERD ALERT: What is DE or Diatomaceous Earth? It’s a white powder composed of fossilized skeletons of one-celled organisms called diatoms. This powder is added to the filter and attaches itself to the grids inside creating a DE cake. This cake, along with the filter grids inside, help to filter out very fine particles. DE filters are the best type of filter when it comes to cleaning your pool, but require a lot more work to maintain.
If you have any additional questions about backwashing a DE filter, I encourage you to ask in the comments below.
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