I'm very late in posting on this, but i've been absent from the forum for a few months.
Like everyone else I love the setup! It's giving me many ideas on what to do with my new tank upgrade. Like you I just got a 55 gallon for free. I have had my RES for 18 years now, so he's quite a bit bigger than most of the turts on here. So I have a few more issues to consider than most, such as size and weight factor of Mr. Turtle. I am wanting to get some plants for him but can't decide if he will just tear up artificial ones, or real ones for that matter! He's never had them before.
I'm definately going to steal your rubbermaid rock holder idea! He loves to play with rocks, but i've had to remove them because he makes so much noise moving them around! It will also be a great way to add his bubble stone back in. He always dislodged it from the bottom of the tank to where it would float.
Anyway, thanks for the ideas! Keep us posted how everything is working out for your little guys