Hi, I've been a long-time browser, but never posted before. Learned all kinds of great stuff on here and have had fantastic results the last two seasons after switching to the methods prescribed on here. Saving money and the pool chemistry is spot-on. I didn't quite know where to post this, because the Spa Forum seemed to pertain more to detached spas and I have a question about the spa attached to my inground pool. Didn't really find anything searching either.
I am in California, so the pool just stays open all winter. We've had light surface ice a few times, but the anti-freeze setting on the pump has been enough to prevent problems. No one closes their pool here and even those without an anti-freeze feature don't seem to have too many problems. My question is: Is there any danger using the spa when water temperatures are in the 50's, other than wasting a lot of propane? Are there any concerns about damaging the PVC pipes going to the spa because the water is so hot and the ground and concrete surrounding them is colder than normal? Any more likely to have a fitting fail, crack, etc.? Anyone else use their inground spa regularly in these temperatures? I know PVC is not usually used for hot water, which struck me as a bit odd that's it's used for the spa in the first place.
The pool is a 15,000 gallon inground, with attached spa. It was built in 1989 and has been resurfaced at least twice that I know of. The last time was about 3-4 years ago, right before I bought the house. I'm not sure if any plumbing was repaired at the time, but I don't think anything was upgraded. The plumbing is either 2" or 2.5" schedule 40 (can't see it right now, but I know it's not 3"), except the conduit going to the light niches, which is Schedule 80. The heater is a Pentair 300K BTU propane unit and the water returning to the Spa gets pretty darn hot after it gets up to temp and the heater cycles on.