- If you want bulletproof - sand is a great choice.
- Low maintenance would lead one to cartridge.
- The cleanest water might lead you to DE.
- All three types of swimming pool filters work.
- You can add a little DE to a sand or cartridge filter to increases its ability to filter small particles.
- Flocculants can be added to the pool water to create big particles out of small particles (think - flocks of birds are easier to see).
- Cartridges that become fouled can be replaced.
My recommendations? I would go with a high-end cartridge filter for my swimming pool. The reason is that no one really wants to have another item on the to-do list and good cartridge filter can last a season. Be sure that you:
- Plumb a line into the drain port with a ball valve, so that you can bypass the filter when you are vacuuming the pool to waste.
- Use a little DE powder (1 or 2 coffee cans full in the skimmer) to really polish the water or just add a flocculent every now and then.
- Take a look at the filter housing design. You may want to consider how easy the filter is to access and clean.
- Keep in mind that the more square feet of cartridge, the less often you touch it.
- Never use a car wash wand to wash the filter. A hose with a sprayer will work fine.