AEA -- Congratulations on the cat pooping in the LR!!

Good for her! Good for you! I might keep her in LB Bootcamp for a couple more days until she is using it more regularly... but who am I? You know your cat best.
As per your post above, I checked the ingredients of the Nutro cat food (the kitten variety) I have been feeding the cats and found it does contain some corn meal! Decided to try a heavier "meat" type dry food so switched to Innova Evo -- 50% crude protein -- to see if it clears up Nuba's runny stools. In checking cat food ingredients I found that Chicken Soup for the Cat Lover's Soul lists blueberries (and no corn meal) if you want to give that one a try at some point.
You could try selling those empty cartridges to someone on the forum if you list them with no crystals... and the shipping shouldn't be too much... consider that in your charge.
New on this end of the LR trial, the LR passed the power outage test this a.m. The kitties used it during the outage and when the power returned, it automatically cycled and that was that. A very LARGE clump was produced but it broke up a bit headed for the drawer and went in with no problems.
The LR is much more challenging to keep clean than the SF (but we knew it would be). A wipe out once a week will be mandatory with my cats. I have "practiced" several times this week due to Nuba. I am using a small lamp to see the insides of the globe. I cycle the LR until all the litter is contained behind the screen, and the hatch is open inside to the drawer. I stop the cycle and use a wisk broom to sweep down any remaining litter and dust. Next I wipe out the inside of the globe with sanitary wipes and follow that with a damp cloth to remove the odor of the wipes, drying it with a small towel, cycle it back to its "use" position, and wipe anything I might have missed. I haven't timed it, yet, but I would guess it takes about 10 to 15 minutes. So far, the inside looks and smells clean afterward.
Anyway, I am glad to hear your cat has initiated the LR with its poop! Hope she continues and the LR works out for you.
UP-DATE on Innova EVO cat food. Cat that was having problems did well on it; caused diarrhea with the other cat so am trying some foods with less protein, no corn meal.
Kitties: Zen & Ariel. Litter Box: Litter Robot. Remembering Nuba, Ceba, and Yang Su Ling.