CanadaGirl

Hello everyone, We bought a Caldera Geneva spa a few months ago and have been more than pleased with it. We also bought a drop test kit as recommended here. We started out on dichlor only but quickly ran into issues of high readings and potential over stabilization. As a result we switched to dichlor then bleach on our water change about 3 weeks ago. Got our CYA to 30-40ish based on measuring a fixed amount of dichlor the switch to plain 8.25% bleach. Bleach is added slowly with the the water running. Noticed today that the area where I normally add the bleach (in middle as much as possible but really over lounger) there is a rough patch. Worried I’ve damaged the shell from the bleach! I didn’t think this was possible, but maybe it settled there? Our water chemistry is as follows: CH about 100 TA: 40 pH: 7.5 and stable CYA: 40ish Any advice is welcome! I don’t want to switch back to dichlor but don’t want to risk damaging our new tub either. Thanks in advance.