how would you give calcium to an aquatic turtle? use liquid in his water? or will they go on land and hunt crickets that have been dusted?
some will, some wont. Some powder will stick to bugs dropped on the water surface.
You can make up your own turtle blocks and include calcium and vitamins.
Cuttlebone (grated for babys) whole for larger turtles, is a great source of calcium.
Whole live feeder fish are better still.
Freshwater crayfish/crawfish, freshwater shrimp etc are also good.
pellets are ok, but fresh is best for anything. Some species wont touch them.
I never liked to use them much, when I did, I soaked them first till they stopped expanding.