For mine, i only dare put them near water, when their yolk sac is already very-very small. Before that, i usually put some damp tissues/paper towels as substrate. Just keep humidity quite high, and warmth as well. After a while, i start adding more and more water to the tissue (kinda like a swamp effect), until i am quite confident that they may go submerged. And, the tissues are also used by the turts as a hidding place (they may actually burrow underneath it), of course you would want to put more than one layer. And dont forget to change the tissues every day.
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My "babies" :
1.0.0 Indo BTS (Tiliqua gigas gigas)
0.0.1 Rainbow skinks (Mabuya multifasciata)
0.0.3 RES (Trachemys scripta elegans)
0.0.4 Amboina box turtles (Cuora amboinensis)
1.0.0 Chinese softshell (Trionyx sinensis)
1.0.0 Asian leaf turtle (Cyclemys dentata)
1.0.0 Leopard gecko (Eublepharis macularius)
And still growing...