Developer Exhaustion Confusion

Okay, I'm confused! Although that may be a normal state of affairs, I need this cleared up.

This goes back to my earlier questions on the Jobo Expert Drums. Jobo states that the maximum amount of solution that should be used with the 3005 tank is 630ml. But, if you want to process the full five 8x10 inch negatives, that is only 126ml per sheet of film. What about developer exhaustion? Acording to Kodak, you need at least 240ml of developer to completely process an 8x10 inch sheet of Tri-X 320 in D-76, and prevent developer exhaustion. So, I take it that you either have to process less than five sheets, or you have to do something else. What is that something else? I can't see why Jobo made a five sheet tank, if you can't process that many at a time!

What am I missing?

Thanks,

Jon

In my experience, Kodak's recommendation is conservative. I develop five 8x10's (usually HP5 Plus) in a Jobo 3005 using 4 ounces of straight D-76 per sheet, or 20 oz total. The resulting negatives have sufficient density and contrast to print at middling contrast grades, which is usually what you want.

Increasing the developing time beyond my usual results in increased density and contrast as you'd expect, which says that the developer is not exhausted.

I would not re-use that developer. But as one-shot, it seems to work OK for me.

Developer is pretty cheap; I would only use it as a one-shot thing, no matter the manufacturer's recommendations.
As for the JOBO, I use a twelve sheet (4x5) tank with HC-110 dilution B; I use 640mL of solution for the twelve sheets and have never encountered any problems whatever.
Like Oren said, if you follow the JOBO instructions, and use one-shot developer, you should be fine.