Fast Buds recommends 9:1 ratio water with rubbing alcohol and it can be used in flowe It works just fine to get rid of mites and their eggs. Just keep an eye out for more mutes after. The problem people have is mixing it too strong. I've seen 1:1 ratio but that is wayyy to strong.
9:1 are the magic numbers
900ml water and 100ml rubbing alcohol (73% version)