My comment about the rock was sort of an educational purposes sort of thing. I figured it was some sort of injectable molded plastic made to look like a rock, there are lots of things like that on the market. However, someone less astute might look at it land think its OK to have a real rock like that. I myself never liked things like that because they are hard to clean.
Your UG system is actually better than the one I used to use in one aspect. Because I was pulling everything into the gravel (and making fertilizer) the gravel because heavily intercalated with particulate material and had to be cleaned quite frequently. The way you've got it you shouldn't have to clean the substrate all too often. However, when the young ones get older there isn't a filter in the world that will remove the scat (too heavy) and you'll be doing some gravel cleaning anyway. Not unless filters have come a long way since my youth, and casual inspection suggests they have not.
I used to throw in a couple Danio (zebrafish) for the turtles to chase. The fish were (and are) inexpensive and quick, so the turtles usually couldn't catch them. And if they did, well they made a nice snack.
Okay, thanks. I'll be clear about the "rock." It's stayed clean so far, actually. I run it under the tap once in a while, but it doesn't seem to need it. In any event I wouldn't bother going overboard cleaning something that costs $6.99 to replace at my local PetLand. Considering all the money I've sunk into this habitat (pun intended), the cost of the basking dock is trivial.
I figure I won't need the catfish any more once I replace the tank (they're only in there as vacuum cleaners because some parts of the tank are hard to reach with a vaccum), so I'll put them in one of the fish tanks and replace them with some zebras (and maybe plecos) when I put the new one up. I just got a stand yesterday (actually, a $35.99 table from IKEA; I bought two extra legs at four bucks each for good measure), so I may do the initial setup later on today or tomorrow.
The water quality in the established tank is textbook-perfect. So I want to steal some Fluorite and water from the established tank and put it in the new one, let it sit a few days with heat and aeration, and then add the rest of the fluorite and just enough water for the canister filters to grab when my order comes in.
Then I'll let the filters run a few days with just floss to clear the fluorite mud, move the tank to its permanent location, add the rest of the water and the plants, put the permanent media in the filters, wait another day or so, test the water, and introduce the turtles.
This sounds like a lot of work, but I'm enjoying it immensely, lol. It's like reproducing a tiny version of the Almighty's creation, right here in my office.
Thanks again,
-Rich