Had to drop my water level a little, the is a bit of a white ring at the old level, 32 day old water. I tried a nylon brush it helped but i can still see it. What can i do to remove it without harming the tille?
TA 60-70.
I consider a CSI of 0 to -0.3 ideal. Aim for that range. To lower the TA you might end up with a temporary CSI that is very negative but that is unavoidable and will not cause damage because it is short-term.
The acid will dissolve some of the grout but if you want the ring gone, the only other option is a pumice stone or a calcium eraser.
Far easier than any of that is to prevent it from forming in the first place.