Ahhhhhh! Aeration it is! I didn't consider the ozonator to be doing aeration, but it actually makes sense. It produces ozone which is highly reactive and gets turned into oxygen. With the water saturated with oxygen, the excess will turn into tiny bubbles -- very similar to an SWG except in that case the bubbles are hydrogen gas.

So, using Trichlor tablets for chlorine is a decent thing to do since they are acidic -- it helps in your situation (even though it doesn't help enough). But the Trichlor tabs will keep adding CYA to the pool so you might check on the CYA level to make sure it hasn't gotten really high.

As for solving the pH rise, you can "prove" which area is the worst problem by selectively turning off different features and noting the change in the pH rise. I see three basic groupings of features you can look at: exterior aeration such as the waterfalls, internal aeration from the jets (not regular returns, but jets that include sucking in air so bubbles come out), and the ozonator. If you can turn these three areas off individually, then you can see which, if any, is worse than the others. Then you can maybe put some of the areas on timers so they aren't "on" as long. That's my best suggestion at this point.

You could add Borates to reduce the "rate" of pH rise, BUT you'll still end up adding just as much acid over the same time period -- just doing so less frequently (so instead of a some acid many times it'll be a whole lot of acid fewer times). You (probably) won't get the benefit waterbear and others have seen with using Borates because the algicidal properties will reduce chlorine consumption but that won't have you cut down the ozonator time since it doesn't generate chlorine. So that's why I don't suggest borates for this particular situation. Of course, I could be wrong (wouldn't be the first time!).

Richard