It specifically says in the directions, "Never allow powder to mix in water (caking occurs)". This stuff is intended to dust the rodents before feeding, but everyone has advised me to not feed him for 4 - 6 weeks...
Okay so I'm not crazy lol yeah my bottle says the same. I'd never heard of mixing it in the water before. But, hey, if it helps, it helps.
Yes, it dusts the feeder, it's fine to wait until the feeding to give it. It helps with digestion.