Wow...four Leucs in a ten....Hmmm...maybe a month...two tops. I've been amazed about how quick my little guys have grown up. I feed mine a lot maybe that has something to do with it. You could ration them and stunt their growth

....I'm just kidding. Im just playing with you because you seem very level headed.

Anyways, I agree I do tend to like to keep babies in something smaller than the 65 gallon but I think the ten will be just too small. As far as the yellow of the great stuff showing ...it wont be. First skim a thin layer of black silicone on the glass, let it dry and then do the great stuff. Then when the greatstuff is dry and carved put the black silicone over it and while the silicone is wet pack on the "dry" coco fiber. You wont see any yellow. A razor blade will get the excess silicone off the glass. They also sell black GS but it will not eliminate the silicone step. I keep my pump in my tank. I just have it off to the side with a rock over it for easy access. I do not bury the tubes but instead hide them under moss, leaf litter or behind plants. I would not have to destroy my tank to get it out. You can use anexternal canister filter to pump the water but you do have to have one that is strong enough to pump the water out if a 24 tall. They can get expensive and not really needed. I hope you show us the build as it goes. Also...one last thing. Only use the GS and silicone that is for windows and doors. Do not use the kitchen and bath stuff because they have mold inhibitors that are harmful to the frogs.