I decided to revive this thread, because I was speaking with one of my customers a few days ago, and he told me something that he was told by the company that sold him his hottub. I had noticed that the water was becoming dull, so I told him it was a good idea to change the water. He was going to change the water himself. So the following week I talked to him again. He told me that he hadn't changed the water, but somehow the water had become sparkling clear again. He told me that he had a service guy out to repair the speakers in the hot tub, and they told him to run the jets with the cover propped up slightly to let some air pass in and out.
I'm wondering if this is a legitimate way to clear up a cloudy tub, given the right situation, and how/why this works. I should also mention that the chemistry in the tub is always pretty good. The tub uses a Frog floater system, which consists of two cartridges, one bromine, the other a mineral pack. I adjust pH and TA weekly, and I add OxyShock once a week as well.