Quote Originally Posted by fluffypanda View Post
a good rule of thumb is 10 gal for every inch of shell. but its not saying if you have four 1in turtles then put them in a 40 gal tank. its saying a ten gal
I disagree - four 1-inch turtles means a 40 gallon. The rule isn't about space, it's about water quality and how much water there is (more water = more stable water quality).

The other rule is 3x the gallon size in filtration, so you need a 120 gallon filter. This is why aquatic turtles are not "starter pets".