Welcome to the club. I fired my pool guy 3 weeks ago. On his last weekly visit, he added a chlorine tab and left in less than 4 minutes with no brushing or water testing at all. I guess he forgot that I have security cameras. Our pool service took a nosedive over the last two months after our last guy passed away, and a new company took over the service. I also noticed very bad calcium scaling on my spa tile that I literally had to chisel off. The SS rim plate on my spa light had also severely rusted in the last month or two, and I've seen more and more small hard brown stains appearing. After reading the forums here, I ordered a test kit and downloaded Pool Math to take control of my pool. My CYA was off the scale at way over 100 thanks to the years of Trichlor pucks, and my CH was only 125. I've done a partial drain to lower my CYA slightly below 100 with more partial drains to come to get it around 60, and I already switched to 10% liquid chlorine. I boosted my CH to over 250 with CaCL, so I'm close to getting my pool chemistry under control once the CYA comes down. My wife recently commented how clear the pool water is now that I took it over.
Be prepared to spend more time and money once you take over managing your pool. I may be slightly addicted, as I've started poolsplaining to my wife, and I even jumped into a Facebook discussion after someone asked for suggestions to fix their green pool. It had over 150 responses, and I was the only one who mentioned TFP and the SLAM process and testing their water before doing anything else. There was a handful of pool contractors and also pool cleaning services recommending phosphate removers, so they are clueless.
My Stenner pump/tank is on the way, and I will be installing a wifi box/timer to control it this weekend. New spa light rim, gasket, and led color bulb on order. Last weekend, I acid washed my spa to remove all of the built up scale. I'm also planning on changing out our tiles and resurfacing the pool deck and plaster the pool/spa later this year, which will be $15K. Next up is maybe a pool robot and automation...
& having a trouble free pool ! 
