I've got the same sort of question,
Damascus
, but for slightly different reasons... mine being mostly that space is limited & my wife doesn't want to see, and then I'm cheap & suffer 50+% import duties & monstrous electricity prices.
So, as
wednesday13
has noted:
Sand filters for above-ground pools are a fraction of the cost of the similar pond-device (EG:
https://www.amazon.com/Pool-Sand-Filters/b?ie=UTF8&node=1273009011) so I think about oversizing the canister with a replacement pond-bead/media & a low-wattage pump - Jabeo's my usual go-to, but there seems some question as to running them out-of-water (rather than submerged).
Then...
There's some question as to the backwash actual-clean without an air-blower, even with the Ultima, so a sand-can with the pond media might expect annual tear-down. However, my office always has a half-full SCUBA tank kicking around, so I wonder about plumbing an old BCD's LP inflator fitting into the intake for a few 120PSI bursts into the backwash cycle. Q: How terrible an idea is this?
And, if not terribly terrible, could I forgo the specific pond-media & stick with the far-less-costly sand & double the backwash schedule?
It's a pond at ~1800gal over-planted & under-stocked, and erring to blackwater so with a big charcoal bag at the exhaust for 'extra' BB. If this works, I may do similar for the bigger aquariums in/around the house, as I don't fully trust my home-made HDPE canisters from old chemical drums, epoxy putty & air-line O-rings. Knock wood.