"she could put it on gravel, like fish gravel."
Well if you use gravel make sure its really large as turtles tend to eat rocks and not all of them pass through and impaction is sometimes an issue. Lots of people use "river rocks" but anything bigger than the turtle's head will suffice.
The other ways to go are:
(1)tiny substrate particles (a fine sand) which is most natural but may ruin filters if the water is not deep enough or the intake tubes aren't protected.
(2) none at all (easier to keep clean, harder for turtle to walk on)
As far as the salt thing goes there are several reasons to use or not use it but in general unless the terrapin is a wild caught adult, its not needed. You will find many different opinions but it has now been shown that terrapins can live in completely fresh water for along time and reproduce and age well with no complications. this seems to work best with cb individuals; wc terrapins can be harder to acclimate to fresh water. Do dechlorinate the water though, with some standard fish water conditioner (there seems to be indications that chlorine is casuing problems with gut flora in turtles).
Keep in mind that a 45 gallon tank may be good for a turtle between 1 and say 4 inches but after it gets larger than that its too small. Terrapins are sexually dimorphic and the difference arise in size: females get much bigger. A female terp will require way more space as an adult (think 125 gallon tank)
Terrapins rarely leave the water except for egg-laying or to drink fresh water if they are in a brackish area (this is a serious condideration and complication if you use salt in the aquarium water) so there is no need to make an elaborate land area. Just make a basking area at least twice the surface area of the turtle. Make use of the space for swimming.
Don't forget an underwater hide/sleeping place. This will help reduce the stress on the turtle.
You may wish to consider getting an aquarium background or some paper or cloth to cover several sides of the tank. Terrapins are sensitive and sometimes shy and seem to feel safer when there is no reflection of "another" turtle and when they can feel protected by the darkened sides.
Terrapins are pretty highly carnivorous (although still technically omnivores) as turtles go. Many keepers use smelt, silversides, shrimp, tuna, clams and some low protein turtle or fish pellets. some terrapins will eat greens and water plants, many will not. There are of course pros and cons to using live insects and fish but these mainly involve the issue of the cleanilieness of the feeder animals (of which, as a snake keeper, you doubtless are aware)
Hatchlings ans juveniles are usually fed on bloodworms and blackworms (first live as they will eat little else, then later, frozen) tiny crickets (getting larger as they turtle grows) small size turtle or fish pellets and small bits of fish.
Do not underestimate how often you will need to clean the water...Get an ammonia-nitrate-nitrite test kit (marketed for fish aquariums) and use it. And there's no such thing as too much filtration. (just watch out that the turtle doesn't get blwn away by the filter output if it is small)
There is an excellent e group at:
terp group
If you join and read through the archived messages you will find many discussions on every terrapin topic that will ever arise.
