Your filter system is the backbone of clear pool water. If the pump moves the water, the filter is what removes the dirt, oils, and fine debris that make water look dull or cloudy. For above ground pools, the “right” choice usually comes down to three filter types: sand, cartridge, or D.E. (diatomaceous earth)—each with a different balance of clarity, maintenance, and convenience.

Below is a practical way to pick a filter system that matches your pool size, how you like to maintain your pool, and the water clarity you’re aiming for.

1) Start with pool size + turnover (the simple sizing method)

To keep water looking consistently clean, most pools are filtered multiple times per day. A good rule of thumb is to size your system so it can circulate your pool water in about 6–8 hours (often called “turnover time”).

• Bigger pools need more flow (GPM) and/or longer run time
• A larger filter tank / more filter area usually means better performance and fewer cleanings
• Avoid pairing a strong pump with an undersized filter (high pressure, more frequent cleaning)

2) The 3 main filter types (and who they’re best for)

Sand filters (Good — The Original Standard and most common choice)

Sand filtration is the classic, proven setup. Water passes through a bed of sand and debris gets trapped in the media.

Why people choose sand:

• Straightforward and durable
• Easy routine cleaning using a backwash function (typically via a multiport valve)
• Great “set it and forget it” option for most above ground pools

What to know:

• Sand filters commonly use #20 silica sand which can be found in most big box hardware stores
• You’ll clean the filter by reversing water flow (backwashing), which uses some water and may require filling the pool a little bit if backwashing for extended periods of time

Cartridge filters (Better — clearer water with less water waste)

Cartridge filters strain debris through pleated filter media. They typically catch finer particles than sand and don’t require backwashing.

Why people choose cartridge:

• Often noticeably clearer water than sand
• No backwashing (saves water)
• Great for pools where you want simple plumbing and steady performance

What to know:

• You’ll clean the cartridge periodically (remove, rinse thoroughly, and 'deep-clean' as needed)
• A dirty cartridge can restrict flow—so cleaning schedule matters

D.E. filters (Best — “polished” water clarity)

D.E. filtration is the high-end option for water clarity. The filter grids get “pre-coated” with D.E. powder, which traps extremely small particles.

Why people choose D.E.:

• Excellent water clarity when maintained correctly
• Captures very fine debris for that “sparkling” look

What to know:

• You’ll follow the manufacturer process to pre-coat with D.E. powder (commonly added through the skimmer while the filter/pump is circulating water in standard 'filter' mode)
• Maintenance is a bit more hands-on than sand or cartridge

3) What to look for in an above ground “filter system” (not just a filter tank)

When you’re shopping “systems,” you’re usually choosing a pump + filter combination. Key things to compare:

• Pool compatibility: rated flow for your pool size
• Filter capacity: bigger tank / more media or cartridge area usually = longer between cleanings
• Valve setup: multiport valves are common on sand (and some D.E. setups)
• Connection size: make sure hoses/plumbing match your pool (common above ground connections are 1.5")
• Serviceability: drain plug, pressure gauge, easy access for cleaning/winterizing

4) Quick “which one should I buy?” guide

• Choose Sand if you want the most common, reliable setup with simple backwashing
• Choose Cartridge if you want clearer water and don’t want to backwash
• Choose D.E. if your top priority is the clearest water and you’re okay with a bit more upkeep

5) Common mistakes that cause cloudy water (even with a good filter)

• Not running the system long enough each day
• Ignoring the pressure gauge (rising pressure of 5 lbs or more usually means “time to clean”)
• Mismatching pump and filter size
• Waiting too long to clean cartridges or backwash sand/D.E.
• Forgetting the basics: empty skimmer/pump baskets, keep water chemistry balanced, and maintain steady circulation

Need help selecting the right above ground filter system?

If you want a quick recommendation based on your pool size and how you like to maintain your pool, call the Pros at 888-352-7582 or email us at [email protected].