Swimming Pool Filter Reviews - Cartridge & Sand Filters
Your swimming pool filter accounts for over 50% of the total water clarity in your pool water. Balancing chemicals is obviously important to maintain clear water
however a dirty, improperly maintained filter - or a filter that is not sized correctly for your pool system - will make it impossible to keep the water looking clean
and clear. In order to determine which filter, and which model size of filter, you need for your pool requires a calculation involving the volume of the pool and the
flow output (GPM) from the pump. Unfortunately most pool technicians do not, or can not, perform these calculations instead relying on using a rule of thumb for which
filters will work on which pools. As the pool owner you should not assume that anyone else has properly sized your equipment and you should double check all values
and perform a filtration turnover calculation before purchasing a replacement filter.
How To Figure Out Which Size Filter You Need
To begin the process of selecting your new pool filter you need to calculate the volume of your swimming pool. Measure the length, width and depth using feet and
round numbers. You do not need to be 100% accurate in determining your volume.
Rectangle pools - Multiply Pool Length x Pool Width x Pool Depth x 7.5 = Pool volume in gallons
Round Pools - 3.14 x Pool Radius x Pool Radius x Pool Depth x 7.5 = Pool volume in gallons
Kidney Pools - Average Pool Length x Average Pool Width x Average Pool Depth x 7.0 = Pool Volume in gallons
Now that you have the pool volume in gallons, multiply that number by three to determine the daily turnover value in gallons that we need to achieve. Passing the entire volume of water of the pool through the filtration system 3 times every 24 hours is an industry standard for residential swimming pool and hot tub water safety. Once you know the turnover rate you need for the pool we can look at the pump and filter sizing requirements that can accommodate this turnover.
Pool Filter Maximum Flow Rate Design
Every pool filter has a maximum amount of water flow that it can handle while maintaining its filtering efficiency. Too much flow can damage the filter head,
multiport valve, laterals, and cartridge paper - just about every part of the actual filter. Even if the filter does not blow up from high flow rates the mechanical
wear on the internal components of the filter will wear quickly and dramatically reduce the longevity you can expect to get from it.
As an example the popular 24" Hayward Sand filter, S244T, has a maximum designed flow rate of 62 GPM
At 62 gallons per minute, this is 3720 gallons per hour, 29760 every 8 hours and 89280 gallons every 24 hours. Now since our turnover rate is three times the pool volume we can take the 89280 gallons per 24 hours and divide it by three to determine the maximum pool volume that the Hayward S244T can handle. This comes to 29760 gallons which means this particular sand filter can theoretically filter pools up to 30,000 gallons operating at its maximum capacity.
When sizing your filter you are always better off to slightly oversize a filter as opposed to slightly undersize it. In the example above we calculated the S244T being able to filter up to 30,000 gallons. In practice it would be extremely difficult to size the pump to allow you to get exactly 62 gallons per minute in the field. Also, you do not want to run your filter at its maximum flow rate but instead you want your filter to meet your turnover rate while operating at 80% of the maximum GPM flow rating it can handle. This will put you nicely into the middle of the maximum and minimum effective flow rates for your system which will allow you to filter the water without any problems meeting turnover rate while not driving water through the filter at the absolute maximum flow it can handle.
Keeping with the above example when you reduce the maximum flow rate of the S244T filter to only 80% of its maximum flow value we determine that this filter is optimally sized to pools up to 24,000 gallons.
How To Match Pump And Filter Sizing Together
The heart of your pool filtration system is the pump and this plays a large part in sizing your filter to your swimming pool. In the previous example we looked at the
maximum GPM flow rate that the filter can handle - the pump is what will determine the actual flow rate of your system. In order to determine the flow rate that your
pump provides we need to consider the manufacturer rating for flow rate for your pump model and motor size - as well as take into consideration the flow dynamics of
your installation. The flow dynamics are calculated as the resistance to flow, measured in total head pressure, and this determines the rate at which your pump can
provide water flow.
Your pool system will increase in head pressure for every pipe fitting, valve and piece of equipment installed. Also, the longer the total pipe run, the greater the resistance to flow that the pump must overcome due to friction losses of water traveling through the pipes. It is not possible, or practical, to actually calculate your total system resistance to flow for the average pool owner. This would only be required in commercial applications where every aspect of the pool filtration system must be designed to meet specific and stringent commercial pool water requirements. In the average residential pool you would assume head values as follows:
Average pool = 30 feet of total head pressure
Lift to rooftop solar heater = add 1ft head pressure for every foot of vertical lift to the heater
Pump location more than 60' from pool location = add 10 feet of head pressure
Pump more than 5' above the height of the water level in the pool = add 10 feet of head pressure
Again, these are general values provided to give you a basic understanding of how resistance to flow factors into the flow rating that your pump can provide. For most swimming pools you can assume 30 feet of head pressure and look up the pump flow rates for your model and size pump operating at 30 feet of head resistance to flow and this will be fairly accurate as to what your pump will actually provide once installed on your pool.
Example - A Hayward 1 horsepower super pump, SP2607X10A, has a maximum flow rate of over 80 GPM however this is only theoretical since the pool pump would never be used on a system where there is no resistance to flow. Assuming a resistance to flow of 30 feet of head pressure the maximum flow rate for this pump drops to 65 GPM. If you were to locate the pump further from the pool or make it push up to a solar heater the resistance to flow could easily become 40 feet of head or more. At 40 feet of head this pump could only provide 54 GPM.
A Complete Example Of The Calculation For Sizing Pool Filters
Assuming a 16x32' pool with a 3.5' shallow end and 8' deep end, pool volume can be assumed at 20,608 gallons.
Average depth is (8+3.5) / 2 which you would them multiply by 16 x 32 x 7 = 20,608 gallons.
This means the turnover requirement is 61,824 gallons every 24 hours. This means an hourly turnover requirement of 2576 gallons and a per minute rating of 42.9. Assuming 30 feet of head pressure resistance to flow in an average pool installation we then need a pump that provides at least 43 GPM at this range. The 1 horsepower Hayward superpump we looked at in the earlier example would be able to provide up to 65 GPM at 30 feet head which is a fair bit more than this pool needs. Sizing the pump down to the 3/4 horsepower superpump model, SP2605X7A, provides up to 52 GPM at 30 feet of head so even this pump is a little larger than actually needed but fits well within the scope of this example pool.
So we have determined that 52 GPM is the closest pump flow rate that meets this pool turnover requirements. We then need to match this flow to a suitably sized filter. The Hayward 22" sand filter we looked at earlier, S220T, has a maximum flow design of 52 GPM so it appears that this filter could be used with this system however it would be beneficial to have a filter slightly larger than the minimum required size as we discussed earlier. The next size up Hayward sand filter is the 24" S244T model which has a maximum GPM flow rating of 62 GPM. This means that our pump providing 52 GPM would only realize approximately 80% of the total flow the filter is capable of handling which is a great combination to allow for clear water without overworking the filter.
Swimming Pool Sand Filters VS Cartridge Filters Comparison
The two most common kinds of pool filters are cartridge filters and media filters usually filled with silica sand or similar fine granular straining media. A third
kind of pool filters, DE filters or diatomaceous earth filters are popular in certain regions however sand and cartridge comprise the majority of the filters in the
residential pool industry. Sand filters are older technology and have been the most common style of pool filter for the last 30 years. Cartridge filters are
relatively new, and provide quite a few advantages over traditional sand filters, at a price.
Filter particulate size
The size of particulate that a filter removes is a pretty good indicator for the quality of the filter. The finer a filter can strain the water, the less turbidity and floating debris you will have in your pool water. Sand filters typically will strain material down to 15 microns in size where cartridge filters perform much better removing material down to as little as 5 microns. A cartridge filter will strain material 3 times finer than that of a sand filter.
Maximum flow rates
In general, due to the design and way the filter operates, cartridge filters are capable of handling much higher flow rates than similar physical sized sand filters. A Hayward S244T filter which is often used on fairly large pools up to 20x40 in size, has a maximum flow rate of 62 GPM. A comparable sized Hayward cartridge filter also used on 20x40 pools would be the C4030 filter which can handle up to 150 GPM! Even the very smallest cartridge pool filter Hayward makes, the C2030, can handle up to 84 GPM so you can clearly see how flow rates are less of a factor for cartridge filters than sand filters. This one factor becomes very important when you are considering that new pool pumps are very powerful and often can provide flow rates that far exceed what even fair sized sand filters can handle.
Both sand filters and cartridge filters require maintenance but on very different schedules. Sand filters require a process called backwashing which reverses the flow of water through the filter to clean the debris out that has accumulated. This is something that you would do every 7-14 days with an average pool installation - and more often during periods of time where there is more debris in the pool such as in the fall. Cartridge filters however do not have a short maintenance cycle such as this instead requiring disassembly and deep cleaning of the filter cartridges any time the pressure in the filter rises 7+ psi over the clean filter operational pressures. For the average seasonal pool in cold climate areas this will usually only be once per pool season usually done when the pool is closed for the year. Year round pools with cartridge filters will need to clean them once to twice per year on average.
There are times when one filter will be a better option than the other under certain circumstances. Recently salt water pools have become very popular in residential markets causing some densely populated municipalities to ban discharging salt water to the road side where pool water has always traditionally been discharged. The damage from salt at concentrations of 3000ppm is appreciable enough that it is expected that salt water pool discharging bylaws will continue to become more popular. In these areas it is expected that you will drain your pool into the house sanitary system or onto your property without flooding to the neighbors property. For periodic repairs and maintenance this is an inconvenience however for sand filter owners is simply may not be possible to backwash the filter which is required, often, in order for the filter to continue doing its job. In certain circumstances like salt water pools in protected discharge areas a sand filter may not be an option for you.
Upfront & ongoing costs
Sand filters represent the entry level market for pool filters. On average a cartridge filter of similar capabilities will be three times as much money as a sand filter. While the cartridge filter does require less ongoing maintenance, can handle higher GPM flow, and will filter three times finer material from the water the upfront cost will be prohibitive to many pool owners. Further to this, sand filters have a reputation for running for long periods of time without requiring service. Cartridge filters use a paper filter medium which simply does not last as long as sand media and will require replacement every 3-5 years as an average number. As cartridge filter owners will tell you, replacement cartridges are very expensive which is something you will need to consider before making your purchase. Replacement filters can cost between 40%-75% the replacement value of the entire filter.
Sand Filters For Small Swimming Pools
Hayward S166T - 100 lbs sand media, 30 GPM Max flow rate for pools up to 11,500 gallons
Hayward S180T - 150 lbs sand media, 35 GPM Max flow rate for pools up to 13,500 gallons
Pentair TA40D, 144126 - 175 lbs sand, 40 GPM Max flow rate for pools up to 15,500 gallons
Sand Filters For Medium Sized Swimming Pools
Pentair TA50D, 144127 - 225 lbs sand, 50 GPM max flow for pools up to 19,250 gallons
Hayward S220T - 250 lbs sand media, 52 GPM Max flow rate for pools up to 20,000 gallons
Jandy SFTM22 - 250 lbs sand media, 66 GPM max flow rate for pools up to 25,500 gallons
Hayward S244T2 - 300 lbs sand, 62 GPM max flow for pools up to 23,750 gallons
**This model is a 2" multiport valve. A 1.5" valve is also available under part number - S244T
Pentair TA60D, 145241 - 325 lbs sand, 60 GPM Max flow rate for pools up to 23,000 gallons
Sand Filters For Large Swimming Pools
Hayward S270T2 - 350 lbs sand, 74 GPM Max flow rate for pools up to 28,500 gallons
Jandy SFTM25 - 350 lbs sand media, 83 GPM Max flow rate for pools up to 31,750 gallons
Hayward S310T2 - 500 lbs sand media, 98 GPM Max flow rate for pools up to 37,500 gallons
Pentair TA100D, 145240 - 600 lbs sand, 100 GPM Max flow rate for pools up to 38,500 gallons
Hayward S360T2 - 700 lbs sand media, 142 GPM Max flow rate for pools up to 54,000 gallons
How To Choose The Right Sand Filter For Your Pool
With so many options it can seem intimidating choosing the correct filter for your pool. To make the process simpler all of the sand filters shown on this page
represent the most popular, reliable name brands and models of sand filters in the pool market. There are many off-brand and no name brand filters for sale however
choosing a tried and true make and model is money well spent. Having to recover your water quality even a single time can negate the cost savings of choosing a
cheaper no name brand filter over a more recognized brand name.
In the pool industry many people are brand loyal having a preference between Pentair, Hayward and Jandy/Zodiac usually based on previous experiences with a particular product. So long as the filter that you choose is sized appropriately for your pool any of the brands and models on this page should be a good option. Failing all other reason, choose a filter brand that matches the pump or the rest of equipment on your equipment pad.
The Difference Between Sizing Sand Filters & Cartridge Filters
With a sand filter it is important to match the GPM output of the pump to the GPM max flow rate for the filter. With a cartridge filter this is not the case since
cartridge filters in general can handle flow rates much higher than sand filters. The concern for damaging the filter due to excessive flow is almost non-existent
except for the most powerful of pumps matched with the smallest of cartridge filters.
The consideration with cartridge filters is the effective filtration area size, measured in square footage. The larger the square footage of filtration area the better the filter will operate and more importantly the longer in between cleaning cycles. As a cartridge filter gets dirty you will experience an increase in the system operating pressures due to the increase of resistance to flow as the water has a more difficult time passing through the filter paper and debris that builds up on it. Since every pool experiences a unique amount of debris in the water there is no hard rule as to how to size cartridge filters except to say that you want to have a filter large enough that you only need to open and clean it once per year for seasonal pools and twice per year for year round pool installations.
To give you a guideline as to how to determine what cartridge filter square footage size is suitable for your pool consider the following general guideline:
The hourly flow rate for turnover divided by 12 will give you the appropriate filter square footage size - Using the 20,608 gallon pool from the earlier example you could calculate the turnover rate in 24 hours at 61,824 gallons. Divide this by 24 to get the hourly flow rate of 2576 gallons. Divide the hourly flow rate by 12 to get the filter square footage size, in this case 215 sf.
Cartridge Filters For Small Pools
Pentiar CC50, 160314 - 50 sf filter area for pools up to 5000 gallons - Max flow rate of 50 GPM
Hayward C751 - 75 sf surface area for pools up to 7250 gallons - Max flow rate of 75 GPM
Pentair CC75, 160315 - 75 sf filter area for pools up to 7250 gallons - Max flow rate of 75 GPM
Jandy CS100 - 100 sf filter area for pools up to 10,000 gallons - Max flow rate of 100 GPM
Pentair CC100, 160316 - 100 sf surface area for pools up to 10,000 gallons - Max flow rate of 100 GPM
Hayward C1200 - 120 sf filter for pools up to 11,500 gallons - Max flow rate of 120 GPM (1.5" Ports)
Cartridge Filters For Medium Sized Pools
Hayward C1200-2 - 120 sf filter for pools up to 11,500 gallons - Max flow rate of 120 GPM (2" Ports)
Jandy CS150 - 150 sf filter area for pools up to 14,500 gallons - Max flow rate of 125 GPM
Pentair CC150, 160317 - 150 sf filter area for pools up to 14,500 gallons - Max flow 150 GPM
Hayward C17502 - 175 sf filter area for pools up to 16,750 gallons - Max flow of 120 GPM
Jandy CS200 - 200 sf filter area for pools up to 19,000 gallons - Max flow of 125 GPM
Pentair CC200, 160318 - 200 sf filter area for pools up to 19,000 gallons - Max flow rate of 150 GPM
Hayward C2030 - 225 sf filter area for pools up to 21,500 gallons - Max flow rate of 84 GPM
Pentair CCP240, 160310 - 240 sf filter area for pools up to 23,000 gallons - Max flow 90 GPM
Jandy CS250 - 250 sf filter area for pools up to 24,000 gallons - Max flow rate of 125 GPM
Sta-Rite (Pentair) S7M120 - 300 sf filter area for pools up to 29,000 gallons - Max flow 100 GPM
Cartridge Filters For Large Swimming Pools
Pentiar CCP320, 160340 - 320 sf filter area for pools up to 30,500 gallons - Max flow 120 GPM
Hayward C3030 - 325 sf surface area for pools up to 31,000 gallons - Max flow rate of 122 GPM
Jandy CL340 - 340 sf surface area for pools up to 32,500 gallons - Max flow rate of 127 GPM
Sta-Rite (Pentair) S7M400 - 400 sf filter area for pools up to 38,500 gallons - Max flow rate 115 GPM
Pentair CCP420 - 420 sf filter area for pools up to 40,000 gallons - Max flow rate of 150 GPM
Hayward C4030 - 425 sf filter area for pools up to 41,000 gallons - Max flow rate of 150 GPM
Sta-Rite (Pentair) S8M150 - 450 sf filter area for pools up to 43,000 gallons - Max flow 124 GPM
Jandy CL460 - 460 sf surface area for pools up to 44,000 gallons - Max flow rate of 150 GPM
Sta-Rite (Pentair) S8M500 - 500 sf filter area for pools up to 48,000 gallons - Max flow 130 GPM
Pentair CCP520, 160332 - 520 sf filter area for pools up to 50,000 gallons - Max flow 150 GPM
Hayward C5030 - 525 sf filter surface area for pools up to 50,500 gallons - Max flow rate of 150 GPM
Jandy CL580 - 580 sf filter surface area for pools up to 55,500 gallons - Max flow rate of 150 GPM
Hayward C7030 - 725 sf filter area for pools up to 70,000 gallons - Max flow rate of 150 GPM
How To Choose The Right Cartridge Filter For Your Pool
With so many options of cartridge filters available on the market it can be a little overwhelming trying to determine which one is the best match for your pool. While
cartridge filters can handle a fairly high flow rate some of the new generation of pumps, variable speed pumps and large motor pumps greater than 2 horsepower can
potentially be too powerful for some cartridge filters. Be sure to choose a filter that has a high enough flow rate to handle the volume of water your pump moves.
Oversizing your cartridge filter larger than what your pool requires will result in needing to open and clean the cartridges less often. This is certainly a benefit as opening the filter and cleaning the cartridges will take your pool down for at least 24 hours. The down side to oversizing is that replacement cartridges are expensive and the larger they are the more expensive the upfront cost of the filter as well as ongoing replacement cartridge costs every 3-5 years on average.
Tips For Installing Swimming Pool Filters
Before you attempt to install any swimming pool equipment you should take a look at the video series from Swimming Pool Steve that reviews installations of pool equipment for deficiencies. Additionally there are sections on pipe materials, plumbing fittings, glue, primer, unions and valves commonly used for installing pool and spa equipment. If you would like to learn more about how to install a pool filter correctly as part of a pool system read the Installation Tips from Steve.