Size Waterbowl?

I currently have plastic containers in the snakes cage's (rack system housing 17 Ball pythons) in 41QT tubs. I'm trying to figure out how wide diameter i need for there water dish. (guide for hatchlings up to adults would be appreciated :)
-Austin

I just give them a bowl big enough for them to soak in if they wanted to!

4 inches for adults is fine contrary to a popular belief BP rarely soak.

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