Ok this may seem extreme.
We got a 1997 Grandee for free** (see below). We spent less than $300 replacing the the pillows and several of the jets, then we sprung for a new cover another $400. Pretty darn cheap for a tub that looks and runs like new. We love our tub and wouldn't consider getting a new one.
BUT
I was looking at the ACE water care system and really liked it but I can't justify buying a new hot tub just the get the ACE system. So I began to wonder what would it take to upgrade all the electronics in my 1997 tub to be able to install it.
I think it could be done for about $2,500. My spa had the latest 2010 heater installed just before we got it.
Breakdown - no labor I'll do it
IQ 2020 approx. $475
Control head approx $240
Control panel approx $75
Misc. cable $100
ACE system $1200 - if I can even buy it seperately
Are there other ACE like options out there? Are they as good?
**Ok free is a relative term I had to upgrade our electrical service to 200 amps and install the spa sub panel. Bid was $2,600 I did it myself for < $1,000
Backyard didn't pass the WAF (wife acceptance factor) bid on work was $5,800. I pulled the permits rented a bobcat did all the excavation plus I put in 2 retaining walls for just over $1,300. Still needs sod (not in original bid) but I am waiting until it cools off.
So far I have spent about $3,100 on this free spa. I'd do it again in a heartbeat because I really needed it after all that work.