I've worked with both sand and cartridge, but not DE. For me, when looking towards future pools, I only see cartridges. Here's my thinking so far:
Cartridge:
1. Cleaning cartridge takes time, but i listen to audiobook or music, so I use the time well
2. On the few times when I slip up and get some green, I can have it crystal again in a few short days.
3. During the 350 days a year my pool is absolutely perfect, it is as crystal clear as is imaginable to me or any of my many guests (I don't have a pool light, so I can't speak to the particles that might be visible at night, don't care)
4. I get a really nice peace of mind that the filter is clean because I can see it with my own eyes after each cleaning
5. No water loss during cleaning YAY!
Sand: (***My sand filter was undersized*** so keep that in mind when reading these, and when buying yours, don't skimp)
1. During clean up after a green swamp - constant CYA loss during backwashing was annoying and costly, took weeks to get crystal
2. went from a couple PSI away from backwash time to backwash time real, real fast, like sometimes a few hours
3. Take this one as a bonus if you're a fisherman/woman - when backwashing, dozens and dozens of worms come to the surface
4. But so does all the nastiest water you've ever seen flooding over wherever you backwash, including particles that made it through your skimmer and pump baskets
5. Lived in constant fear that spider gasket/gear would fail - man I was broke then and that would have been a hardship
6. Had the pipe that leads down to the radials stick to the top when removing it once, and pulled the radials out by accident, risking damage
7. have to be careful when deep cleaning or risk damaging radials
8. Had the occasional fear that my sand was settled in some places, making pathways of least resistance, not actually filtering optimally - wow I was a worrier back then!
9. Positive - had the option to try adding DE or Cellulose Fiber if I ever wanted to
10. Maybe positive - if I had to ask someone to maintain my pool for an extended time - backwashing might be less to ask a neighbor than closing the valves, pulling and taking the hose to a cartridge
Assumptions that exclude DE for me:
1. Would have to buy that box that traps DE on backwash because I refuse to dump it on lawn or put in stormdrains/sewer/septic
2. Would have same water/CYA loss issues during backwash
3. Why am I spending more/complicating things when I've achieved a crystal clear TFP with both sand and cartridge?
4. Might really consider it if I had a seriously illuminated nighttime pool and I was bothered *IF* I was unable to get the results I wanted with cartridge or sand
Final thoughts:
1. No matter what you go with, make sure it is BIG enough for the pool you have and the debris that you expect to have to deal with - especially if you live in a windy area/trees/flowers/dirt/pollen!
2. Unless you have seriously strong feelings - or just want to switch - your money might generate more happiness for you if you invested it, paid off debt, did some extra self care, donated it, or whatever - both sand and cartridge (with appropriate size and flow) are ridiculously low maintenance ways to keep a pool filtered and I'm grateful to their inventors/improvers
3. Anyone else helping take care of the pool? Would sand be easier on them? I know lifting a large cartridge can be harder on the weak, elderly, or those with joint issues compared to turning a dial to backwash.
4. If you go cartridge, I suggest the investment in a $6 fireman style brass hose nozzle
5. If you live in a water-restriction or high chlorine cost area - cartridge wins, no contest for me
6. If your pool is a perfect storm of pollen and dirt blown in - maybe sand saves you time on maintenance overall?
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If you do decide to go with a cartridge filter have a waste line plumbed in just in case. It is very handy in case you ever need to drain some water.
I totally agree! Not necessary, but I've wanted this feature a few times during hurricane/rain season when it overflows and further floods/erodes the surrounding area instead of the corner of my property where I'd rather it go