I would definitely get rid of the sand...they're too small to be on it. Most pet store employees don't have a clue what they're talking about... Anyway, I don't recommend repticarpet either because thier claws can get caught in it...which could cause them to lose toes or drop their tails. I'd recommend running to Lowe's or Home Depot, or Menard's (or whatever you've got near you...lol) and picking up some vinyl tiles. Get stone looking ones without a glossy surface. You can cut them with scissors to fit the tanks. They are very cheap (less than $2 a tile for 12 x 12" tiles), and look very good! They also hold heat well and are very easy to clean. I recommend vinyl mostly because you can cut them with scissors, but also because they make VERY tight "junctions" between them and there won't be any cracks for toes to get stuck in!. You'll probably get self adhessive ones, and I'd recommend sticking something to the bottom of them or just leaving the backing on them so that you can take them out to do thorough cleanings more easily than if you had them adhered to the tank. Anyway...as far as the male thing...you may as well go ahead and keep that one in the 10 gallon when you get the 20 gallon (make sure its a long and not a tall!). Just keep an eye on all of them over the next 5 or 6 months to find out thier sexes for sure!
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Christina

Leopard Gecko Morph Descriptions
2.3 leos
-0.1 tangerine het rainwater albino w/jungle background (Blinkers)
-0.2 jungles (Vahz & Skissor)
-1.0 tremper albino (Spitfire)
-1.0 tangerine rainwater albino (Bronx)
-ignorance is not to be punished when one is trying to gain knowledge...what scares me is the vast number of people who, when given the information to gain knowledge, choose to ignore it.