Hello, joined a few months ago and have just moved into a home with a pool. Tested with TF-100. Used an online pool calculator app to see where to go from here, but replacing 65% (due to high CYA) of our water is not an option right now. Any suggestions where to start? Water is very clear but with a ton of scaling (co-op well water) and some black gook climbing near waterfall areas on stones. Not concerned with the scaling right now but need to focus on high CYA and absent chlorine. Had previous owner's pool boy out and am confident he was insane because he told me the gook was "normal" and the scaling was inevitable with well water. Paid him to explain equipment and give me a rundown on what he was doing to care for pool and it involved putting pucks in a float in the hot tub so chemicals ran into water. We have a instant puck chlorinator that he didn't use because "it constantly clogged". Previous owners left huge boxes of shock that I assume they used a ton. Any tips on where to start? (i have no intention of using pucks but I added in case it helped info) Sorry if above is too much info, any advice would be greatly appreciated, thank you.