You can keep using pucks if you want til you get your CYA where you want it. Just keep an eye on your pH. Trichlor is very acidic. A chlorine reading of 7.5 won't last too long in the Texas heat in a pool with low CYA so its not a worry. Besides, you have a gunite pool and higher chlorine levels are not a problem as they could be in a liner pool.

Did you take a look at the Best Guess Chlorine Chart in my signature yet?