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Let’s update our Smart Pools talk on Sand Filters vs Cartridge Filters… It seems everyone has a different opinion on which system will work best.  We have used both systems for 30 years now on our On-ground pool installations throughout the Cambridge, and Kitchener area, and would like to share some of the facts about each.

The capital cost of each system will be our starting point.  If you are considering an On-ground pool, then it is very likely that budget matters!  While size does have a bearing on the costs of these two systems, the relative price difference between them remains fairly consistent.  The cartridge filters cost about 3 times the equivalent size or capacity sand filter.  Almost half of the cost of these cartridge filter systems is the cost of the filter cartridges found inside the tank.  These cartridges will need to be replaced about every 3 seasons to be effective.   While the sand filter medium is relatively inexpensive to purchase, changing the sand is a complex and labour intense process.  The filter sand will usually last about 5 seasons before it should be replaced.  As this can be a tricky operation, it should be done by an experienced swimming pool technician.  These changes usually lead to other component failures within the sand filter system and, for this reason, Smart Pools recommends that you replace the entire filtration tank and sand medium at the same time.  It is much more cost effective and will ensure that you enjoy another 5 seasons of uninterrupted enjoyment.

In terms of regular maintenance, both will require your attention several times throughout the swimming season.  The frequency of this maintenance depends mostly on how much dirt and debris make their way into your pool each week.  For residential swimming pools that use a winter safety cover OR have quite a bit of organic material close by (garden beds, trees and shrubs, as well as bugs!), you may need to clean your sand filter medium every two vacuuming cycles or every two weeks (every 4-5 weeks for cartridges)   For those yards that have very little in the way of yard debris you may only need to tend to the filter once every 4-6 weeks (even less for cartridges).

Cleaning the cartridge filter is quite a bit more labour intensive than the sand system.  It requires a few tools and a large volume of water from your garden hose to be done effectively as the pleats in the cartridge are usually quite full of debris and require a lot of attention to flush… see before and after photos below.


New cartridge


Cleaning or “backwashing” your sand filter will use about a half inch of your swimming pool water and is best done when the pool is overfilled from a recent or heavy rainfall when you are recommended to lower the water level for proper filtration.  While you will be discharging some of your salt from the pool, it would actually take 4 or 5 of these backwash cycles to significantly reduce the salt level in the pool.  Replacement salt bags cost about $10/ 50 lb. and you may need one bag per season due to backwashing.  The actual backwash cycle only takes about 30 -60 seconds.  But you should budget about 5-10 mins for the process to lay out and re-gather your backwash discharge hose, which should reach out to the closest roadbed or catch basin.

It is a fact that the cartridge system can remove smaller particulate matter from the swimming pool water beyond any sand filter’s capability.  However, this difference in water clarity is not visible under most conditions. In fact, it can only be detected at night when the pool lights are on AND the filtration system is turned off allowing one to see the tiny particles in suspension.

At Smart On-ground Pools, we are committed to providing you with factual, value-based advice so that you can make good decisions for your backyard swimming pool.  For your best value, save yourself a few dollars and cut down on maintenance time- Sand filtration is the way to Go!

Have a look at some of our other blogs regarding Variable-speed pumps vs. regular single speed pumps for your residential on-ground pool!