it is not necsessary to flush before water curing. i didnt water cure anything my last harvest, but the one prior to that i didnt flush before water curing. it came out perfectly fine.

if youre harvesting at the correct time, bud growth should have peaked by the time youre flushing, so the difference between using nutes or not using nutes is very minimal.

also after doing a 7 day water cure, the buds will air dry very quickly(for me they were 100% dry from leaving them on a rack in a closet overnight) so unless youre really hard up for weed, i would advise against a dehydrator. however, im paranoid about using any type of outside heat to help dry.

basically to water cure you keep your buds completely submerged in water for 7 days. change the water every 24 hours. thats about it. you lose taste/smell/looks but keep potency. works wonderfull for people who want to smoke a cureed harvest asap.