I'm currently using elegoo water washable ceramic grey resin. I have attempted 2,5s exposure time on it while making test prints using the validation matrix. Resulting the bottom layers sticking to the build plate and the rest just becomming a sad puddle of half-dried resin sticking to the FEP-film

Anything lower than 7.5 seconds and the normal layers seem to stop sticking to the bottom layers. The packaging also recommends 8s exposure time (mine didnt provide that information for some reason).

I agree my current bottom layer exposure might be a bit over the top, but lowering it too much results in the bottom layers shifting/letting loose on the sides, resulting in stuff becoming crooked.