I don't have access to the cistern.
The plumbing in this place is interesting. They pump desalinated water into a vault under the building, which is then pumped to a tank on the roof and gravity feeds to the apartments. Each bathroom has its own tank type water heater hanging up near the ceiling. During the summer if you want hot water you turn on the cold tap to take it from the roof, and for cold water you use the hot tap to take it from the tank in your air conditioned apartment.

I think I have it resolved. I took the lid off of the tank and adjusted the float to fill it with more water, to flush it more thoroughly. That seems to have been effective- I did it a few days back and the stench has gone. Who knew that an exorcism only needed a bit of extra water and some liquid bleach?
( The Resident Loon Not a demographic. Do not measure., Sat 15 Sep 2012, 6:59, Reply)