As someone who kept a 75 gal. mbuna (Malawi) tank at one point, it is true that they can go without food for a couple days. In fact, it's considered a good idea to fast them once in a while - I hear it keeps the bloat away.
8 days is a long time, though. One suggestion would be to get a few algae clips and put a few large romaine lettuce leaves in there. Not sure how many fish you have - my fully stocked tank could go through a lettuce leaf in a day with no problem (when they got big, it was faster than that).
However, there's the problem of the lettuce leaves rotting and getting _ into the filter before they even provide food.
Another thought might be to put some cheap plants in there that won't die right away in the high pH. Mbuna love plants (and it's a healthy diet for them)
Anyway, just my $.02
- Amy