First, breathe. Any time you get a new snake you would be safe in assuming that it has mites until proven otherwise. I always treat my quarantine enclosures the day before the snakes show up.
Second, treat the enclosures or tubs, rack, and paper substrate for the new snakes with the RID spray and ensure it's dry before putting the new snakes into their new homes.
Third, use the RID similarly on the paper substrate and enclosures for your current snakes to help prevent them from getting infested. Do not spray it directly on the snakes and ensure the paper and tubs are dry before putting the snakes back.
Fourth, get a bottle of the Frontline spray from SBK's video posted above and treat the snakes like he does when they come out of the shipping box. If you do this you shouldn't soak the snakes.
Fifth, you have no business purchasing any more snakes until you can set up an effective quarantine area; mites are not the worst thing that can befall a keeper.
Finally read my post #13 in https://ball-pythons.net/forums/show...elp-asap/page2