I've been reading up on the dichlor-then-bleach method and would like to make the switch. Ever since buying the spa this past March I've been using dichlor as the chlorine source along with non-chlorine shock (weekly). My first water lasted two months before it needed to be changed. I'm now on month three after the water change, and it still looks good but I doubt I can get another month out of it if I keep using dichlor alone.
The current readings (using Taylor K-2006) are:
TA 80, CH 190, pH 7.2, and CYA 100
The spa is 310 gallons and it DOES have an ozonator.
I have not added any borates knowingly, nor do I have the means to test for them currently, but at the water change I added a product branded by the local spa store that they call "Silky Smooth". It's a very thick white liquid, almost like latex paint. There are no ingredients on the bottle but I'm wondering if it could be a borate-type product like Pro Team Gentle Spa since the product descriptions are similar. I will say that before adding the Silky Smooth the rotating jets were kind of "jerky" whereas after adding the product they spin freely. So it had some effect on the water.
My question is whether you think I can switch over to bleach with the water in it's current state, or whether I should do a water change first. I'd prefer to keep going on the existing water just so that I can get further into the fall before doing a water change which would then hopefully enable me to get through the winter without having to do one at the coldest time of the year. I live in Rhode Island.
Are there any adjustments to the chemistry recommended? My saturation index is a little low, but I'm thinking that the pH might come up simply by making the switch away from dichlor over to bleach. The CYA is obviously high, but not much that I can do about that without a water change.
Thanks in advance for any advice!