New tub owner (about two months now), and goodness has this forum been illuminating. I've learned a ton from reading all the great thoughtful content here. THANK YOU!!!
We purchased a new HotSpring Grandee with the Freshwater Salt System (I'm not sure if I'm going to hang onto the salt system, but that's for a future post; TLDR, seems expensive over the long term?). I think maybe I had from-factory-biofilm, because it didn't seem like the salt system was keeping up. Sure, I was adding dichlor (no bleach) on every use, but FC would just be so low. After several weeks, I got myself a Taylor K-2006, and after another week I measured the amount of this mysterious chemical cyanuric acid, and wow, I was probably 120 ppm or so (yes, off the charts). Hrm, I better understand what this stuff is.
Fast forward tons of reading later (mostly this forum, thank you!!), plus a half drain/refill and then later an ahhsome purge (gross green stuff!) and full drain/refill, and I think have a decent (novice) sense of hot tub water chemistry (bonus: salt system now appears to actually be generating a decent amount of FC, so seems like the ahhsome purge worked?).
My question is (and I'm 95% sure I saw the answer on this forum somewhere, but for the life of me I cannot find it now):
A major recommendation on this forum is to add dichlor until your cyanuric acid hits 30-40 ppm; originally people were recommending 20 ppm); then switch to bleach. But then I have to either a) measure the cyanuric acid regularly, or b) calculate how much I should expect to add based upon volume. Why not just add one single dose (or maybe one almost-enough dose followed by a measurement, followed by a few tiny adjustment doses) of cyanuric acid followed by enough bleach to adjust the FC to the proper ppm? This seems like it might be easier? Or is there something I'm missing?
The Taylor kit reagent R-0013 for the cyanuric test comes in two 22mL bottles, and each test consumes 7mL, so that's basically 6 tests of cyanuric acid before needing to order more. Not a lot of tests to work with if you're trying to dial it in.
Am I doing it wrong? (I wouldn't be surprised if I was.)
Thanks again for all your help (past and possibly future)!
PS - I started keeping a hot tub lab notebook starting at my ahhsome purge, in case weights are needed.