I am located in germany and use simplemining. Tested the ram temps in windows so i know all is safe.
Could push the ram higher, up to 104 mhs eth.

Never changed to coolant. Over time (months) it will become less a bit and i fill it up. Checking the water
all 4 to 8 weeks. I would go for DP Ultra coolant with a color. (i have always green)
This will help in case you have a leakage.

My 1080s run watercooled since they came out, years ago.