they look really nice~
I just use deli cups.
I glue one of them to the bottom of the tank and then put a new one on top of it. Thus if the water bowl gets too dirty all I have to do is throw it away and use a new one.
I think that I got my 'water bowls' for $50 dollars for 2500 of them~~ (or something like that)
But yours looks a whole lot better than mine~~