Bud, Sherry, and everyone else at Formulary:
Yours is a horn well worth tooting. Every single transaction I've had with you guys has been satisfying. You guys have a specific product focus, you do it well, and you stand behind what you sell. Yours is an example of the kind of vendor that will go a long ways toward giving regular folks access to silver and alternate process photography in perpetuity.
Alas, I haven't managed to scrounge myself a magnetic mixer yet, but in the past, I've had good luck with the kind of paint mixer paddle you attach to a cordless drill, so I'll try that route. I'm expecting my next shipment of Divided D-76 today.
It's interesting to hear that the quality of borax impacts how well it stays in solution. Once I'd used up my part "B" from Formulary, (and I apologize for not making this clearer in my post) I used grocery store Borax (20 Mule Team) for part B. It sounds like I should just order more photo-grade borax once I get about halfway through my new part B.
As for the particulate in part A, I'll keep an eye on it this time. If I recall, the instruction sheet recommends a shelf life of 2-months and mine was at least twice that old, so again, it sounds like I need to refresh more often.
I know some chemistry retains its life for a much longer time: diafine seems to last until all the part A has been sucked up into emulsion, and Rodinal seems to work well into the time it starts to resemble bad maple syrup. It sounds like I better ensure that my DD-76, though, is two-months old or less, and probably use photo-grade borax for my part B in the future.
Thanks again guys for the prompt posting/reply.