Orlando has very long, hot, and humid swim seasons. This is the main reason why a cartridge-type filter is best here for an above-ground pool.
When I started my pool maintenance business in the late 1980s, most of the Inground swimming pools here in Orlando had sand-type filters. And almost all of the above-ground pools had them.
Over the sixteen-year span of my service business, cartridge-type filters all but replaced the sand-type in ingrounds AND more than half of above-ground pools came with cartridge filters.
THERE ARE THREE TYPES OF FILTERS FOR ABOVE-GROUND POOLS
1 Sand-type
This filter uses sand to clean pool water. Water is pumped through a tank of sand and particles get trapped in the sand with the cleaner water making its way back to the pool.
When the sand has trapped a lot of debris over a few weeks, it is cleaned by reversing the flow of water through the sand and sending the trapped debris out into the yard. This is called “backwashing”.
2 Cartridge-type
This kind of filter uses a pleated element made of a synthetic “denim-like” material. As water is pumped into the filter tank, it has to flow through this element to make it back to the pool. The element traps debris only allowing the water to get through.
When the element has trapped a lot of debris, it is pulled out of the tank and manually sprayed down with a pressure nozzle on a water hose cleaning off the trapped debris from the outside of the element.
3 DE-type
DE filters use grids framed in plastic and covered with the same synthetic type of material used with a cartridge filter element. Only it’s not pleated.
Those grids sit positioned in a tank and are evenly coated with DE (diatomaceous earth) powder. As pool water pumps through the tank, it has to pass through these DE-coated grids. The powder traps debris.
When the DE powder is full of debris, The flow of water in the tank is reversed and the now dirty DE powder comes off of the grids and is pumped out into the yard.
NOTE: The grids in a DE-type filter need to be taken out of the tank body and manually sprayed down with a pressure nozzle on a water hose at least once every 18 months.
WHY SAND-TYPE FILTERS AREN’T IDEAL FOR ABOVE-GROUND POOLS IN ORLANDO
The Central Florida climate is considered humid subtropical. You can look up what that means exactly but for your swimming pool, it means a long and brutally hot summer of high algae growth and chemistry affecting rains.
A sand filter does not trap as small of particles from the water as the other two filter types do, so it’s not as efficient.
Plus, a sand filter is a closed-type filter, which means it is not designed to open up. So, you are not able to look inside and see the status of the condition of the sand. Filter sand can get caked up and stop allowing water to flow through it.
Because a sand filter is closed, half of the sand inside may be caked up and not working and you will never know it. And with it being closed, you can never tell how well the sand got cleaned during backwashing.
They may be OK for a pool in the north where the extreme summer season is a couple of months long and 75% humidity is considered “very humid”.
The summer in Orlando is no joke. And the hotter it is and more humid, the more things like to grow in pool water. This is another big reason I’m not a fan of sand filters in Florida.
With our brutal summer climate and extreme afternoon thunderstorms (not to mention tropical storms), the likelihood of a pool turning green occasionally is much greater.
With their higher micron rating and unknown working status, it takes a lot longer to bring a swimming pool back to clean and clear with a sand-type filter in comparison to a cartridge or DE type.
WHY I AM NOT A FAN OF A DE-TYPE FILTER FOR ABOVE GROUND SWIMMING POOLS
While D.E. filters are the best kind of pool filter in terms of their micron rating (they trap the smallest particles from the water), there are three things that I don’t like about them.
1 They are expensive to buy
DE-type filters are more expensive (comparing same size/quality) than both cartridge and sand filters.
This may be okay for those affording a one hundred plus thousand dollar in-ground concrete pool, but most getting an above-ground pool are on a much smaller, tighter budget.
So, the extra $200-$300 for a DE filter is a much greater percentage increase with above-ground pools.
2 They break more
With my now 38 years of working with swimming pools, I can tell you that DE-type filters break more than the other two. They have grids or fingers inside of them that get holes or break, a manifold that can crack, and multi-port valves or pump handles that can leak or fail over time.
Again, if you have a big money in-ground pool with bells and whistles, you can expect and have a budget for repairs. A filter breaking may not be as impacting if you have a pool service guy who can stay on top of fixing things.
Most above-ground pools are maintained by the pool owner. And in most cases in Orlando, you cannot get a pool repair guy to come out and work on above grounds. So, having a filter that breaks can suck a lot more with an AG pool.
3 DE powder is very toxic
This isn’t something you will hear much. Diatomaceous earth, although harmless looking, is very toxic to your lungs.
During my early years of servicing pools here in Orlando, I didn’t know about DE powder. I would work with it as if it were as harmless as Goldmetal flour.
Then I got some in my eye one day, and it messed up my eye pretty good. I wondered how this harmless white powder could do that, so I researched DE powder.
Turns out that DE powder is such a good filter media because it adheres to and absorbs things well. Under a microscope, it looks like billions of tiny fishhooks. So yeah, whatever DE powder you breathe into your lungs is going to be staying there for a long while.
I want to mention one very positive thing about DE filters. There is no better filter for getting a green pool back to clear again. DE filters combined with someone experienced with turning a green pool around will get the job done days faster than pools with sand filters.
3 REASONS WHY I THINK A CARTRIDGE-TYPE FILTER IS BEST FOR ABOVE-GROUND POOLS IN ORLANDO
1 They work well
Over the last 30 years or so, the elements for cartridge-type filters have gotten better in terms of their micro rating. Cartridge filters are now pretty close to as good as DE filters at removing smaller particles from the pool water.
2 They are a simpler design and have fewer parts
Our current civilization is notorious for complicating just about everything supposedly for the better. Yeah sorry. I don’t buy it.
Cartridge filters are simple. This means they don’t have as many parts that can break or a complex design that can fail.
And they work well, so no need to try to over-improve them. (Ever tried to fix a Kuerig? What a complex joke.)
Simple means cheaper to buy and breaks less, which is great. Especially for above-ground pool owners.
3 They are an “open” system
When you clean a cartridge filter, you have to open up the tank and pull out the element, This allows you to see exactly what is going on inside. If something is clogged or broken or looks bad, you can see it.
With sand and DE-type filters, it’s a guessing game as to how well it’s filtering water inside. They are designed to either never be opened (sand-type) or opened every year and a half (DE-type).
HAVING VALVES FOR YOUR ABOVE-GROUND POOL WILL MAKE IT EASIER
For an above-ground pool, the pump and filter sit below the level of the pool water. This means that any time you have to open the pump basket, filter, chlorinator, etc., you will get a backflow of water coming from the pool.
Plumbing in two valves (1 each for the skimmer and return line) will allow you to turn the water off coming from the pool, which will make it easier when cleaning the cartridge filter.