I have studied at Taasisi twice. It is great, especially if you can get Mwalimu Hassan or Mwalimu Omar. If you can, tell them hi from Amy.
I did two 6 week stints on Zanz. and never got bored. I would just head up to the Northern Beaches (Kendwa is my favorite)and go diving on weekends.
In town, the Florida guesthouse is cheap, clean, private, has your own bath with hot water and very close to Taasisi. That is where I always stay. Best of luck. Amy