Calcium and drought in Texas

You didn't mess anything up. Your unsoftened fill water has a CH level of around 180 ppm (test to confirm). When pool water evaporates, the calcium stays behind. Adding more calcium-laden fill water while topping off increases CH level in the pool.

You NEED to hook up the fill line to your softened water. Once you do, CH levels will stabilize and you may see no CH increase. You may never have to drain again, assuming you avoid solid forms of chlorination.

One option is a reverse osmosis service ($600-$700). The other is a water exchange.

You might consider bead-blasting the waterline. They'll need to drain down about 6-12" of water. Maybe the company will drain down a couple feet of water for you while they're at it, then you can refill with softened water and get CH back in range (depending on the capacity of your softener.

Check out the article below for tips on draining. Consider the No-Drain Water Exchange.

Draining - Further Reading

Forgot to mention, waterline bead blasting cost me about $4 per liner foot (~$400 total) a couple years ago. I can DM the contact info for the company that did mine. Not sure if they service your area.

Okay, I saw Canyon Lake and thought you were near me...turns out there's another Canyon Lake in TX. Your name and the title of the post should have been my first clues...duh.

Forget about the 180 fill water. Test yours.

Forget about the tile cleaner guy here in CA.

Everything else stands.

Read up on Calcium Saturation Index. Maintaining lower TA and pH will help to mitigate scale. Your numbers are already pretty low, but moving forward try to maintain a negative CSI in the range of 0.0 to -0.30. When CH levels get too high, trying to achieve negative CSI becomes nearly impossible.