White stuff on one plant

I'm not sure if it's powdery mildew, I sprayed it right off with a spray bottle. Which if the stuff is powdery, would make sense if it just vanished lol. But it doesn't seem likely that it is powdery mildew, considering the environment my plants are in 79-80 degrees with a humidity of 35% today cause it was freaking hot, and couldn't bring myself to turn the a/c on. I recently had a magnesium deficiency in this, and another plant. Solved it with correcting the PH in those containers, and for the quick fix I put 2 tablespoons of epsom salt in 1 gallon of water. I'm thinking the white mineral could just be salt build up from me misting the plant with water that has epsom salt in it? Would powdery mildew simply spray away if found? Lots of questions here, no pictures cause as I said the shit just sprayed away.

I just went in and sprayed it with a light baking soda solution (quarter of a teaspoon for a 16oz spray bottle). Just in case.

Yeah, pm can just wipe off or even just blow away sometimes. You should now better within the next few days if you see spotting on other places.

Baking soda solution should kill the problem as long as I keep applying it weekly right?

I would think so, baking soda changes the ph of the leaf so the crap can't live. The key is to stay on it.

I used hydrogen peroxide in a spray bottle, went away in two days and didn't harm the bud...

Phew, began to worry if I was being a bad plant keeper. I check my plants multiple times a day, thanks for the help. As gave them a good thorough misting about 15 minutes ago. +rep for info

My plants are just in vegetative still, so the key is elimination and prevention right now for me.

Definitely just salt build up, looked at it under a scope.