Please don't be offended when I say this .......... The fact that your numbers could qualify you as a "perfect water club member" are yet another example of how little some pool stores really understand pool chemistry.

Your chlorine is way too low. Your CYA may not actually be 100. Since 100 is the highest value that the test can differentiate, a reading of 100 means 100 or higher. It could be 150, 200 or who knows!

The minimum your chlorine should be is 8. Never lower. Take a look at this chart that shows the relationship between CYA and chlorine that you should become familiar with:> http://pool9.net/cl-cya/

It is definitely the trichlor tabs you are using and the ones that you linked are still full of CYA and will continue to have your CYA rise.

How many pucks do you have left? Are they wrapped or not?

By the way, your alk is fine where it is.

(I feel like I 'burst your bubble.' If so, I'm sorry........)