Sincere thanks to Dr. Spa for taking the time to provide this information. This is just a follow-up, as I'm fairly confused now about a number of things.
I bought my first tub in California, when I was living there. I'm now in the UK, so my choices are to go with a UK company who imports their wood (or tubs) or to deal with importing myself. I'm working with a company here that has been in business for 26 years and sells a lot of cedar tubs. I spoke with the owner at length yesterday, and he swears to the following:
1. Properly run ozonators will not harm a wooden tub. He claims that the new corona ozonators produce too much ozone, and that while they may cause problems, if the proper amount of ozone is being produced it will not harm the tub.
2. He also claims that bromine should be the preferred chemical in a wooden tub. He argues that it is alkalinity and not acidity that is most dangerous to wood. And further, chlorine is more alkaline than bromine.
3. He went on to say that he thought it was a bad idea to use chlorine in a hot tub *at all*, as the heat of the water simply dissipated the chlorine too quickly and it was impossible to keep a safe and proper residual.
I told him what I had learned here, and also insisted I had had good experience with chlorine in the past. He stood by these arguments.
THIS IS NOT intended as a flame of Dr. Spa or anyone else. I am NOT the expert here, but I am indeed confused that two folks who both seem to have a huge amount of experience and knowledge have come to such opposite conclusions. So I'm not questioning either one of you or impugning anyone's character, it's just that getting such utterly conflicting advice makes it hard for me to make a choice.
All of that said, I will be likely to follow the advice of chlorine and no ozonator, simply because that worked so well for me in the past. Still, I would be very intrigued to here the opinions of other experts out there on water chemistry and the like.
thanks again...