Are there any new developments here? I'm from the Marine section, but I'm going to be doing this very thing. Part of a large backyard redesign with a deck over the pool, Japanese Tea Garden type... The pool is a useless feature as an actual pool. Throwing money away every month for a big wet spot.
From what I've figured out at this point, with vague knowledge of it all, I have some initial thoughts of what can be done...
This is a 16 x 36, 22,000 gallon SEE-MINT pond.

Actually, apparently, it's gunite which I have never heard of until just now. 3' shallow, 9' deep, pump house holds a 1 and 1/2 HP pump, timer, 60 square foot diatomaceous filter. Looks like it's running through 1 1/2" pvc. We're also going to add a waterfall to the shallow end. The heater in the pump house is old and will be pitched and something else can be plumbed into that if necessary. Don't know what - another filter, maybe a DIY? And since it's a pond on a relatively large scale, the chlorine should evaporate off and dissipate with small, more frequent top offs, shouldn't it? A carbon filter canister could be plumbed into the line that fills the pool if necessary.
Definitely want to do this economically, too. From what I've read so far, it looks like I'm pretty much there now, just change the filter media, adapt the waterfall for additional filter real estate... Have I missed anything crucial?
Any and all helpful input appreciated!
Debbie