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How To Clean A Pool Sand Filter

How to clean a pool sand filter
There are only three common kinds of swimming pool filters which are sand filters, cartridge filters and diatomaceous earth filters. Of the three kinds two of the three, cartridge and DE filters, require regular service to open, disassemble and clean the filter media. This is something that can be done as often as every few weeks or as little as every few months or more depending on how much use the pool gets and what the filter pressure indicator is telling up about the pool. With all pool filters as the pressure on the gauge increases this is your indication that the filter is getting dirty and needs service soon.

As any pool service technician will tell you, the stuff you find inside cartridge and DE filters when you service them is pretty darn disgusting. The elements, even on the best maintained pools, are covered in gray sludge, slime, hair, lint, skin and who knows what else, and it is hard to rinse this junk off. It is kind of sticky and saturates the filter media which is why these filters are cleaned with a degreaser solution like you can read about in this article on how to clean a pool cartridge filter. So what about sand filters? They never get opened and cleaned like the other filter types. how do you clean a pool sand filter?

There are a few schools of thought on sand filter cleaning and the first is that you do nothing at all to them. You put sand in them and run water through them until the sand starts leaking out one day long in the future. This is how a lot of people treat their sand filter, for better or for worse. However when it comes time to change the sand in your filter it is actually so bacteria laden that it can cause folicular dermatitis on contact with your unprotected skin. This is why cleaning sand filters made this list of some of the worst things that pool workers need to deal with: sand filters are gross.

If a cartridge filter or DE filter is absolutely disgusting after a few months of operation. So how gross are sand filters after years of operation without ever opening them? Do you really want me to answer this for you? Backwashing is something that all sand filters need regularly and this definitely helps to reduce on the physical debris within the sand, but it is not the physical debris that you are so much worried about. Build up of oils is the main problem for every filter type. unfortunately with a sand filter the backwash process is only going to be minimally effective at reducing on these oils (which eventually develop into sticky biofilm that acts as a food source for bacteria). Backwashing a sand filter is about as effective as rinsing a paper filter cartridge with a garden hose. It helps to remove the physical debris from the filter, but does essentially nothing to remove oils that are saturating the media.

Sand Filter Degreaser

Sand filter cleaning - Something that every pool sand filter owner should do is regularly treat the filter with a deep cleaning degreaser solution. This product is added through the skimmer or pump where you essentially charge the sand filter with this degreaser and then immediately turn off the pump. You do not want the degreaser to pass through the filter and go on back to the pool. You just want to get it into the filter and then turn off the filter for at least one hour time (follow the instructions on the bottle for the product you are using). After sitting for an hour you perform an extended backwash of the pool filter to clean out all of the cleaners (and coagulated oils) out of the sand. It would help to raise the water level in your pool while the degreaser is soaking in the filter so that you can do a backwash in excess of five minutes long without having the water level in the pool drop below the skimmer mouth.

Rinsing a sand filter - After you have backwashed the filter for a longer period of time than your normal maintenance and cleaning schedule it would be a good idea to rinse the filter head before returning to the "filter" setting. Not all filter heads have a "rinse" setting but many do. If you have this option you should perform a 60 second rinse after every time you backwash. This service to flush the head of the filter out with clean water to get rid of any debris that might be stuck in there from the backwashing. Debris within the multiport valve can cause damage to the gasket which will cause the water to be able to escape the gasket. Usually this results in water leaking from the backwash port of the filter when it is running in filter mode. Normally no water should be able to access the backwash line when in filter mode but this gasket failure is common with sand filters.

Water leaking from backwash line - When water can escape through the gasket in a multiport valve on a sand filter you will usually find water going out through the backwash line when you are in normal filter mode. A manual valve on the backwash pipe to control the water loss is the band-aid fix to get you through the weekend, but the real fix is resetting the gasket in the filter head. This used to be a common service point however modern dat pool technicians rarely bother with this anymore. Once the head starts leaking a gasket replacement is likely to only solve the problem temporarily. Something caused the filter to start leaking through the backwash to begin with and it is likely to happen again. Also the gaskets are often held in place with crazy glue which is a nightmare to remove, since it has to be perfectly clean to reliably seal. The bottom line is that when the gasket displaces in the head of your sand filter usually you just replace the head of the filter, or the key assembly, instead of trying to install a new gasket.

Sand filters are easy to ignore other than regular backwashing maintenance. In truth the stuff they collect, and the oils and bacteria that develops in the sand is gross, but also contributes to consuming your free chlorine in your pool water. Using less chemicals in pools is something that everyone wants these days so cleaning your sand filter with a degreaser is something you should do to reduce on the amount of chlorine your pool uses every single day. Honestly if you could see inside the filter you would definitely not forget to clean them regularly. It gets pretty gnarly in there.

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