Everyone's going to stone me for this but go ahead and use the calci sand if you really want to (since you have an adult.) But before doing so, make sure your gecko eats from a food dish so as to avoid impaction, and provide a calcium dish 24/7 so the gecko doesn't mistake the sand for a calcium source. Pay close attention during shedding because you'll probably have to assist with the shed!
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Reptiles:
2.2 Leopard Gecko Morphs
1.0 Bearded Dragon Morph
0.1 Box Turtle (Rescue)
0.1 Albino Ball Python (BHB line)

Amphibian:
0.1 Red-Eyed Tree Frog

Bird:
0.1 Jenday Conure

Pups:
1.0 Black Lab/Pit Bull
1.0 Maltipoo

and lots of tropical fish!

-Patrick