I've been using TFP for a few years now and have finally registered. What a fantastic website!
My pool is a black plaster IG 35K gallons I designed and had built back in 2000. It's shaped like a 65-foot long lawn-mower blade with the deep end in the middle and a seating ledge around the middle circle's edge. The goal was a a reflecting pool (hence the black plaster), a sports pool (with the deep end in the middle), and a lap pool (1/2 Olympic pool length). The decking is 2-foot slate 2" thick.
I live in Maryland where the winters are occasionally cold, yet I've only winterized the pool once. Instead I have the pumps run on freeze-protect switches (first an Intermatic timer unit that died, then an Intermatic PE653 remote control unit that exploded (probably a lighting strike, but it never had enough range), followed by a Len Gordon timer with freeze protect (which is now the backup controller) and finally a Pentair Intellitouch with Screen Logic. In the coldest of winters I can get 2-3" of ice on the top, but I've never had a cracked tile or plumbing or any leaks. Once the power went out for 2 days during a cold snap in the low 20s, but nothing broke. I just had to turn off the breakers so that the pumps would not come on until they had thawed. I did lose a Polaris booster pump because it froze, but that's because the Intermatic PE653 freeze protect only turns on the main pump and not the booster too (on purpose- they thought this was a good idea. Glad that controller died.) The new Pentair Intellitouch controller (new last year) can have both the pump and booster on freeze protect, but I'll be sure to test this with some ice-water before winter. I like to be able to sue the pool as early and late in the season as possible as well as enjoy it a s reflecting pool in the winter, so I don't regret not closing it. The additional electricity to run the pumps is less that the cost of having someone open and close it and a new cover every few years. The only downside is getting all the leaves out of the pool at the end of fall, especially if a big storm or hurricane rolls through (once I had to get a Poplar tree out of the pool that came down in a hurricane.)
While the tile, coping and plumbing have all survived the pool not being winterized, the black plaster has faded to grey and nearly white in some places. It looks like a mottled old pair of acid-washed jeans from the 80s. I tried muriatic acid as a test on a step to restore the color, but the improvement was not significant enough to do it to the entire pool. In some ways I think the mottled look is sort of cool so I'm not inclined to replaster anytime soon. The plaster also has some places where it's etched beyond the surface which is more worrisome, but the integrity still seems perfectly sound.
I switched over from a Jacuzzi huge DE filter to a large sand filter a few years ago. The Jacuzzi was a pain to disassemble and clean with a hose, and you could see when you took it apart that back-washing was leaving a lot of grossness on the grids.The sand filter was a big improvement, and the backwash controls are much easier to use.
Last year I put in a Pentair Intellitouch automation with ScreenLogic control (via PC, iPad). I have a WiFi hub setup in the pool equipment shed which links this via the ScreenLogic serial to Ethernet protocol adapter, and then wirelesly to the house WiFi. The protocol interface stopped working this summer and Pentair promptly replaced it for free - huge kudos to their customer service.
This year I switched to a SWG (Pentair Intellichlor 60, oversized for my pool). It has allowed me to stop using chlorine tabs and the pool is much more stable (I used to have bouts with green and cloudy water from algae.) But the pool water is never really clear-clear; it can be foggy/milky at times and the SWG puts out this from the return jets. Underwater you can see lots of microscopic bubbles (someone said this was hydrogen, a byproduct of the SWG process.) And the SWG, while keeping the pool clear, never raises the FC, even when I run it in shock mode (100%, 24 hours). My pool has lots of residual chemicals probably lurking in the water (algaecides including copper treatments) and I read these could impair an SWG's performance. So this weekend I drained the pool, acid washed the plaster, rinsed everything out, and am now refilling it to give the SWG a clean start. I also intend to remove the sand from the sand filter and clean it out too. I'll post an update once this is all done.
I travel a lot, so the pool needs to maintain itself for up to two weeks at a time. The Rainbow feeder helped as I could load a month's worth of chlorine tabs in it (it had extensions and stood a yard tall!); the SWG is an even better solution. The only thing else to add would be an Intellichem to keep the ph on target, but my ph rarely moves these days and there are several posts that make me question whether these systems work very well.
The last step will be to tie the Pentair Intellitouch control system into my HomeSeer whole-house automation.