The bottled water thing worries me. Unless you have a very small tank (which you shouldn't have with Africans), it would be very difficult to store enough bottled water to keep up with the water changes you should be doing each week. You should be changing as much water as possible. I'd say 50% a week is a good amount. It just doesn't seem that is happening with bottled water -- at least I can't imagine that it is.......
