You've done very well for a 1st post! Very few grasp as much as you have as a newbie.

OK, a few things:
1) I fear you are going to over-shoot your CYA mark. It's never advisable to add everything at once to hit a target, particularly with CYA. It can take 48 hours to a week for it all to dissolve in and give you a true reading.

Tri-Chlor tablets add CYA as well--I think for every 10ppm of chlorine it adds 6ppm of CYA. Plus they are extremely acidic. Keep checking you CYA levels, don't add any more and let us know where it lands. There ARE advantages to higher CYA levels especially in a hot, wet, humid summer, but adjustments must be made. aylad, our Louisiana moderator, finds she must run higher CYA levels than Poconos or I do, in the NE, in order to maintain her chlorine levels.

2) What size pool do you have? Is it vinyl, fiberglass, or hard-sided (concrete, plaster, tile)? Unless it's hard-sided, or you have an SWG, you are worrying over your T/A of 145 needlessly. But with a waterfall I'm guessing it's hard-sided.

But if you are going to lower T/A, you don't want to aerate at the same time you are lowering pH--Aeration, as you correctly read, raises pH. Use the Muriatic Acid to lower pH and bring T/A down with it, then use aeration to raise it. So turn off the waterfall when you are lowering pH, and turn it back on to raise it.

3) I tend to keep it simple. I avoid "acid demand" and our chemistry experts tell us the acid demand test is wildly variable, so I just watch pH and if it's too high, add acid in small increments. Since I have a 20,000 gallon pool, I'll add 1 cup of acid at a time, diluted in a five gallon bucket of water first, then wait and test. With acid, borax, CYA, calcium, etc, you ALWAYS want to add LESS than you calculate--usually 1/3 to 1/2, not more. You can always add more. Add, wait and test, add wait and test.

Caveat: With chlorine, this rule does not apply. If you hesitate, you risk algae. Plus, if as I guessed you have a concrete/gunite/plaster (whatever) pool, it can tolerate unbelievably high levels--where vinyl will begin to bleach out. Yet with both, overshooting your target FC is better than undershooting it.

Despite the tables and the tests, we have found that every pool is different and owners must learn what works in their own pool. Chem_Geek and PoolDoctor can probably explain why when there are two similar pools with the same numbers, one will have a constantly rising pH, and the other a heavy chlorine demand. The moral? Test and track your pool on the basic tests: Chlorine, pH, T/A, CH and CYA and let those numbers dictate what you do. It's almost as if everyone's water has a personality! Hard to believe but after nearly 10 years here, it happens too often not to believe.

4) Testing: I notice sometimes you post FC and CC, sometimes just FC. Does that mean CC is 0 (the target) or you just didn't measure it? You should always measure CC if you are measuring FC. It's always best to post the full suite of tests and in a column so it's easy to follow:
FC: xx
CC: xx (or TC, since TC = FC + CC)
pH: xx
T/A: xx
CYA: xx
CH: xx
You don't need to post the acid or base demand tests.

I think you are in pretty good shape. Just be conservative, use bleach, and keep on top of your numbers and you'll be fine.

Welcome!