How big should should a tank be if you have three turtles?
The proper rule of thumb is 10 gallons for every inch of Aquatic
turtle you have. So if your three turtles each measure 4 inches
long, for example, you need to have AT LEAST a 120 gallon tank.
"No_Tank_is_Really_Going_to_be_Large_Enough">No Tank is Really
Going to be Large Enough
For a group of turtles, no aquarium is ever really going to be
large enough. The post above provides an excellent guideline for
how much swimming space to provide your turtles - but you must also
allow for basking space as well. Your best bet is to look into a
preformed pond (which are available at most home improvement
stores). When set up properly they provide a more natural habitat
(less stressful for your turtles), and are much easier to clean,
light, and heat... they are also far less expensive - allowing you
to spend your money on fixing them up - rather than providing the
bear minimum. :)
That is not true you need maybe about a 30-40 gallon tank.