Your neutrality is clear and your advice much appreciated.
I have a D1 Wayfarer (with ozonator) which we use at least three times a week. We get into the tub "clean", showering (outdoors) before entering. I have the tub set to filter three times a day for 60 minutes.
I admire your insight as to the tub chemistry however I do not aspire to know more than needed to maintain an clean and healthy tub for my family. Especially because we often use the tub after a few rounds in the sauna.
I had been wrestling with the chems for some weeks after an initial six month period of balance. My dealer offerd (at no cost) the Aqu-Finesse as a solution to my desire to keep the tub clean with as low a clorine level as possible.... I figured I'd try it out for three months.
I drained the tub last Sunday, cleaned the liner, changed the filter, refilled and zapped the water with A-F.
Since then the water has been crystal clear, aromatic and the liner feels squeaky-clean. Only the scum-duck was a little dirty in the first days but this is also now reduced to a neglegable level. After each use I "dope" the water with a tad more than the advised teaspoon of chlorine.
I'm interested to see how the filter looks on Sunday.
What I normally do but have not done this past week is religously measure TA, clorine and pH levels. I thought I'd let it ride for a week..... just feel the tub again as it were. The tub feels good.
I understand that we want to try and keep a chlorine level of or about 1.5ppm, however, I don't see a pH level or anything about it's maintanance in the A-F literature. I'm looking forward to your thoughts on this last point.
I will in any case let you know how this story develops.