I am a tried and true victim of this. I recently "bombed" my pool, causing my CYA to rise to 125; which is unrecoverable. The pool store wanted to sell me 215.00 worth of product to try and lower my CYA, which also included a 50% drop in waterline and refill. Then, based on readings prior to draining and refilling, the pool store wanted to hand me buckets and pouches of chemicals to "balance my pool" based on bad water. I refused, and paid the 10.00 fee for the water reading.
I then went online and found a Taylor 2006 test kit, refilled 60% of my pool with fresh water and took my readings. $7.50 in chlorine, $8.00 for 12lbs of baking soda and 3.00 in soda ash and I am almost ready to swim.
Thanks to all who contribute on this site, it makes simple people like me able to enjoy the finer things in life....on a budget!