One of the most important aspects of pool maintenance is the filtration system, which removes dirt and debris from the water to keep it clean and clear. However, over time, the filter can become clogged with debris and lose its effectiveness. Backwashing is a simple process that can help to restore the filter's efficiency and keep the pool water clean. In this article, we'll discuss how to properly backwash different types of pool filters and common problems that people encounter during this process. Please read the entire article not just your section as there are other things mentioned that you should do and observe before and after backwashing.
Types of Pool Filters
There are three main types of pool filters: sand filters, cartridge filters, and DE filters. Each of these filters operates differently and requires a different backwashing procedure.
1. Sand Filters
Sand filters are used for large pools. They are the most common type of pool filter and the most user friendly. They use a bed of sand to filter out debris and contaminants from the water. As the filter operates, debris collects on the surface of the sand, eventually reducing the filter's effectiveness. To restore the filter's efficiency, the sand must be backwashed.
2. DE Filters
DE (diatomaceous earth) filters use a fine powder made from the fossilized remains of diatoms to filter out debris and contaminants from the water. These filter are also typically used on large pools. As the filter operates, the DE powder collects debris and becomes clogged, reducing the filter's effectiveness. To restore the filter's efficiency, the DE powder must be backwashed.
3. Cartridge Filters
Cartridge filters use a cartridge made of paper or polyester to filter out debris and contaminants from the water. Over time, the cartridge becomes clogged with debris, reducing the filter's effectiveness. To restore the filter's efficiency, the cartridge must be cleaned or replaced.
A few notes before you begin backwashing:
*One of the main reasons you would want/need to backwash your pool is if you notice the returns aren’t pushing water as fast or hard as they had been. This is because the filter is clogged and can’t circulate the proper amount of water as fast as it should be able to. Before you backwash stick your hand in the water and feel the return pressure.
After backwashing your filter, you should notice quite a difference in the pressure of the water returning to your pool. You may be able to visually see the water returning with more force. Now stick your hand in and see if backwashing made a difference. If it was time to backwash you should feel a noticeable difference!
Now that you know the different types of pool filters, let's discuss some of the filter equipment and valves. Familiarize yourself with the multi-port. This is the main valve that has all the different options for water flow like filter, backwash, re-circulate, rinse, closed, and waste. There is also a clear plastic or glass sight glass which we will discuss later in this article. Some small cartridge filters will not have this multi-port.
Please note you should always turn the multi-port in the same clockwise direction. There is an essential gasket within the multi-port, always turning it in the same way will help ensure the proper life of your multi-port.
One last important thing to setup or be aware of is where the discharge from backwashing will come out. Most often there is a blue hose rolled up under the pump area. Make sure it is attached to the multi-port and unroll this hose to a place you want the discharge water to go. Some pools have a backwash line set in the ground and goes to a specific discharge area that has been predetermined. In rare cases there is no backwash hose at all. This means if you turn on the backwash feature water will begin gushing out all over the place at the multi-port. This won’t hurt anything but can cause quite a scare and a possible mess depending on where your filter station is located.
Now you should be ready to start backwashing with confidence.
Backwashing a Sand Filter
Steps for backwashing a sand filter using the multi-port valve:
1. Turn off the pump.
2. Turn the valve handle to the "backwash" position. This will reverse the flow of water through the filter, allowing the dirt and debris trapped in the sand to be flushed out.
3. Turn on the pump and let it run for about 2-3 minutes, or until the water in the sight glass or backwash hose runs clear.
4. Turn off the pump.
5. Turn the valve handle to the "rinse" position. This will flush out any remaining dirt and debris from the filter and prevent it from returning to the pool.
6. Turn on the pump and let it run for about 30 seconds to a minute.
7. Turn off the pump.
8. Turn the valve handle to the "filter" position. This will return the filter to its normal operating mode.
9. Turn on the pump.
Common Problems with Sand Filters
1. Sand in the pool: If sand is appearing in the pool, it is likely due to a broken lateral, which is a part of the sand filter that allows water to pass through but keeps the sand in the filter. This can be fixed by replacing the lateral. Make sure you don’t overreact to seeing some sand in your pool. Rain and especially power washing near your pool will kick sand into your pool as well.
It's important to follow the manufacturer's instructions for backwashing a sand filter to ensure optimal performance and avoid any potential damage to the filter.
Backwashing a DE filter:
Steps for backwashing a DE filter using the multi-port valve:
1. Turn off the pump.
2. Turn the valve handle to the "backwash" position. This will reverse the flow of water through the filter, allowing the dirt and debris trapped in the sand to be flushed out.
3. Turn on the pump and let it run for about 2-3 minutes, or until the water in the sight glass or backwash hose runs clear.
4. Turn off the pump.
5. Turn the valve handle to the "rinse" position. This will flush out any remaining dirt and debris from the filter and prevent it from returning to the pool.
6. Turn on the pump and let it run for about 30 seconds to a minute.
7. Turn off the pump.
8. Turn the valve handle to the "filter" position. This will return the filter to its normal operating mode.
9. Turn on the pump.
**DE will come out and accumulate at the end of the discharge hose. This is nothing to be concerned about as long as you placed the discharge hose in a good location. You can also wash any DE away further with a hose.
Common Problems with DE Filters
1. DE powder in the pool: If DE powder is appearing in the pool, it may be due to a tear or hole in the filter grid. This can be fixed by replacing the damaged grid.
2. Clogged filter grids: Clogged filter grids can reduce the efficiency of the filter and lead to poor water quality. The filter grids should be cleaned or replaced regularly.
3. Overuse of DE powder: Using too much DE powder can cause clogging and reduce the efficiency of the filter. Follow the manufacturer's recommendations for the proper amount of DE powder to use. Using a little less DE is always better than using too much.
**DE filters require re-charging: Every time you complete a full backwash cycle. Once your certain of the above steps and the sight glass was running clear water you need to prepare DE for your filter. After backwashing as described above you only need to put about 80% of the DE required for a brand-new filter as you never get 100% of it out during the backwash process. As an example, if you have a 48 square foot filter you would need to add approximately 4 pounds of DE powder. Your filter will have labels showing the size and amount of DE required. If you cannot find these simply look up your exact size filter to find out how much DE your filter needs. Never overcharge your filter, if anything a little less is far better than adding too much!
Making DE slurry: A tin coffee can full of DE is equal to about one pound. Using the 48 square foot filter as the example. Get a clean bucket add 4 tin can scoops to the bucket. Add water and fill the bucket about 3 quarters of the way with water. Use a clean stick, or your hand to mix the slurry you want it to all be dissolved in the bucket. Ensure your pool filter is running on filter. Open the top of the closest skimmer basket to the filter (you should see the water moving) now begin to slowly pour the slurry into to skimmer. Take care not to pour to fast otherwise it may flow into the pool. The idea here is for the filter to suck up the DE which gets trapped on the filter grids providing the best water filtration. After pouring add some more water to the bucket and mix any that did not dissolve and pour the remainder in. Close the skimmer basket and now your job is complete.
It's important to follow the manufacturer's instructions for backwashing a DE filter to ensure optimal performance and avoid any potential damage to the filter.
Cartridge filters:
These filters are most commonly found on smaller, or “pop up” pools.
Cartridge filters do not use the same cleaning process as the other types of filters. On the vast majority of cartridge filters there is no option to backwash. There are always exceptions to the rules. Some older large filter systems do use cartridges and if you find that you have one of these simply follow the above steps. You should also do the following cleaning as well.
Here are the steps for cleaning a cartridge filter:
1. Before you begin the cleaning process, turn off the pool pump to prevent any water from flowing through the filter.
2. Remove the cartridge filter from the filter housing and clean any large debris or leaves from the filter housing.
3. Take the cartridge(s) to the side of your yard or out of the way. Use a high-pressure hose (a spray nozzle works fine) to hose down the filter cartridge, starting from the top and working your way down. Make sure to get all the debris off the cartridge and out from between the pleats. Just get it as clean as reasonably possible without ripping or damaging the cells.
4. **This step is optional and not necessary. Soak the filter cartridge in a filter cleaning solution for 12-24 hours. This will help dissolve any remaining debris that was not removed during the hosing process.
5. Rinse the filter cartridge thoroughly with a hose to remove any remaining debris and cleaning solution.
6. Once the filter cartridge is clean, reinstall it into the filter housing.
7. Turn on the pump and run it for a few minutes to circulate the water through the filter.
8. Turn off the pump and open the air relief valve to release any trapped air in the filter.
9. Finally, restart the pump and let it run normally.
Common problems encountered when backwashing a cartridge filter include:
1. Difficulty removing the filter cartridge: If the filter cartridge is difficult to remove from the filter housing, it may be stuck due to debris buildup. Try hosing down the filter housing and using a filter cleaning solution to dissolve any debris.
2. Debris in the filter housing: If there is debris in the filter housing, it may not be properly trapping debris and filtering the water. Make sure to clean the filter housing thoroughly during the backwashing process.
3. Leaks: If there are leaks around the filter housing or the air relief valve, it may be due to worn or damaged O-rings. Replace the O-rings as needed to prevent leaks.
4. Clogging: If the filter cartridge becomes clogged or worn, it may not effectively filter the water. Make sure to clean or replace the filter cartridge as needed to maintain optimal performance.
5. Ensure you pay attention to the way the cartridge came out of the housing and which end is the top.
Now you should be fully confident on how to backwash and clean your filter properly. Always use care and common sense when using anything near electric outlets, plugs, and water. I will follow up with another article on how to take apart sand and DE filters and carefully clean the cells and internal mechanisms. This is a delicate process and you shouldn’t just attempt it without reading my next article or doing some homework yourself. A full breakdown like this can be done once a year or even every other year or more. That all depends on certain factors we will discuss.
I hope you found this informative. I usually like to make my articles a little more fun, but with so much to cover and so many important things to be aware of I didn’t have much room for anything else. I do look forward to sharing more with you very soon.
Best regards,
From the PoolStainSolution.com team