Appreciate the reply! I think my brain was thinking you'd be 'topping up' but now that seems like not the most common use case.I've watercooled for 19+ years and the reality is that care and patience should always be the utmost priority. If coolant drips or spills, it isn't the end of the world, clean up the spill and ensure that components are 100% dried before ever attempting to turn a system on. Using canned air, paper towels, cotton swabs and even hair dryers and fans help out. I would avoid excessive heat like from ovens or things of that nature.
You could technically submerge your entire PC in water and as long as it dries completely before power is switched on, you should not see any issue. I've had people tell me their computer had been rained on (window left open) and it was shot. Let it dry out over several days, monitor and system were each fine once water was gone.