What is the Best Type of Pool Filter?

jandy filters, sand filter

When thinking about swimming pool equipment such as the pump, filter, and heater, most people will visualize a sand filter.  This is probably the most common type of filter used, but you should know that there are some other options available on the market.  Don’t get me wrong, sand filters are nice and perform very well.  It is just that when you are thinking about purchasing a swimming pool, I think you should be informed of what options you have.  In this post, I will give some information regarding pool filters.  My goal is to inform you on what options are available so you can make the choice of which type will be best for you and you can do this with a certain degree of certainty.

As I have stated above, sand filters are very nice and function fairly well.  However, there are a couple other types of filters available.  You can also get a cartridge filter, or a DE cartridge filter.  The main difference between those two types of filters is that the basic cartridge filter relies on the cartridge itself to remove dirt and other small particles from the water, and the DE cartridge filter uses what is know as diatomaceous earth to remove the dirt and small particles from the water.
Changing the Filter Sand
Before I get into those types of filters, I want to focus on the sand filter.  The quality of filter is based on a few different things depending on your needs.  Generally, a filters quality is measured by the size of particle that it is capable of removing from the water.  The particles are measured in microns, and one micron is 1/1000th of a millimeter.  To give you a better idea of how small this really is, a grain of table salt is roughly 100 microns in diameter.  So your typical sand filter can remove particles as small as 50 microns which is roughly the width of a human hair.  That’s pretty impressive, and as impressive as it is you have to understand that a sand filter requires that it be backwashed to clean the sand of the particles that it has captured.  To do this, they are made with a backwash feature built into them.  When backwashing, the water flows through the sand collecting the particles and ejects them through the backwash port of the filters multiport valve.  When this happens, you basically take the water from your pool and put it in the yard or down the storm drain nearby.  This can be a problem if you live in an area that has laws against putting pool water in the storm drain.  Check with you local authorities for more information.  Additionally, the water you put in the yard or storm drain is full of chemicals, which may be why some law makers have made it illegal to dispose of through the storm drains.  It also seems logical that this water could have adverse effects on the grass in your yard over time.  This isn’t necessarily a daily process, but you will have to backwash from time to time, which means that you will also have to put more water into your pool from time to time.  In addition to that you will more than likely be using your hose to do so, and unless your outdoor spigot is plumbed to your water heater you will be putting cold water into the pool.  Now that water lowers the temperature of your pool and will need to be heated again.  You will also probably have to add more chemicals.  The last thing I want to say about sand filters is that even though you backwash periodically, the sand will eventually get to the point where it is not working as well as it once did and will need to be replaced.  This can be a hassle, and rather difficult to do yourself.  You may want to hire a professional for this just to avoid the headache.
Now let’s look at cartridge filters.  This type of filter uses cartridge elements to remove the dirt and other particles from your pool, and it has the ability to remove particles as small as 20 microns which is better than what a sand filter can do.  The other nice thing about this type of filter is that they do not require backwashing.  This means that you will avoid losing water in your pool, and dumping water in the yard or storm drain.  So for areas with laws regulating where to dump pool water this is a nice feature.  You will also be saving chemicals, and avoiding the need to replace drained off water with cold hose water.  However for this type of filter you will eventually have to clean the cartridge, and over time you will find the need to replace the cartridge all together.  I will say that it is a bit easier to clean or replace a cartridge rather than replacing filter sand.  Another nice thing about this type of filter is that it doesn’t have multiple settings.  You just install it and let it do it’s thing.  It does have a pressure gauge installed on it which will tell you when it is time to clean the filter.
So for someone who has limited experience with swimming pool equipment this type of filter is fairly user friendly.  When it comes time to clean the filter cartridge or cartridges (depending on the model) there are products available that you spray on to them and allow the to sit for ten or so minutes then rinse off with water, or you can use a hose and brush to remove the debris from the cartridge.  Once they are clean you simply put them back into the filter body and close it up.
The last type of filter I want to tell you about is the DE cartridge filter.  This type of filter is similar to a cartridge filter in that it uses cartridges to clean the pool water and doesn’t require backwashing.  So you will get all the same benefits as the basic cartridge filter as far as chemical usage, heating, and so forth as mentioned in the cartridge filter section.  The main difference is that this type of filter’s cartridge is coated with DE or diatomaceous earth which allows the filter to effectively filter out particles as small a 5, yes 5 microns.
Diatomaceous earth is a form of sedimentary rock which contains the fossilized remains of a one celled algae called diatoms.  These diatoms had a hard outer shell made of silica that protected them, and it is the silica shells that are left over in the fossils.  These fossils are full of tiny microscopic holes which is what catches the particles as small as 5 microns in diameter.  These filter cartridges do not come with the DE already coating them, and it is up to you to do so in order for the filter to function properly.  The owner’s manual will have directions regarding the proper coating procedure and how much DE will be used.  The last thing I will say about the DE filters is that diatomaceous earth is considered a carcinogen, and an irritant if inhaled.  To us, it appears to be even finer than confectioners sugar but it is in fact very jagged and sharp.  It is also used in gardening as an insecticide.  If you have a garden and notice that it is full of slugs or snails, you can sprinkle some DE around and as a snail or slug slides over it they will be cut up and eventually dry up and die.  So, while this type of filter is probably the best as far as what it can remove from your pool, you will probably want to take precautions to protect yourself when coating the cartridges with the DE.  Wear a respirator or something to prevent you from breathing in any air born DE, otherwise you may have that scratchy throat feeling for a while.  I know that this sounds scary to some, but let’s be real here for a minute. There are plenty of products available to consumers that experts say cause cancer including diet soda, and cell phones, and yet we still see people drinking diet soda and everyone, even kids, have cell phones these days.  I’m not trying to downplay the seriousness of cancer,  I am simply illustrating the fact that you have to use your best judgement.
I just wanted to give some information about what is available as far as swimming pool filters go.  I think anytime you purchase something it is nice to have as much information as you can so you can make the best possible decision.  You have to do what is best for you.  All of the filters I have mentioned work very well.  Some might work better than others as far as filtration, but none the less, with any of these filters you will have a clean pool.  I hope this information helps, and as always if anyone has any questions regarding any of my posts please don’t hesitate to ask.