I'm trying to get back into processing b&w 4x5 film, since no commercial place around here does sheet film anymore. When mixing up a batch of Ilford ID-11 I found that no matter how vigorously I shook it in a closed bottle, I couldn't get the powder to go completely into solution. I used tap water at 104 F degrees, as per instructions. I would guess that about 1/2 of it did mix in eventually, but even that required a lot of shaking. Clumps are still floating around, and there is a pile of powder in the bottom of the glass gallon jug after about 45 minutes of severe agitation (and aggravation on my part). What should I do?