I agree on the filter. Looks like a more than adequate setup to get started with. Very nicely done.
Also, I'm curious how would you get an AC110 to work in that tank without the water level being too high for the turtle to get out? Most Aquaclears lose suction when the water level drops close to the end of the intake tube.
FWIW, if you want to save money on the filter cartridges, save the framework and buy a $3 bag of quilt batting or similar material from a craft store and then cut pieces as needed to wrap around the plastic framework. I did that in my Whisper 30i and it worked great, plus it's super cheap. This was when I was keeping frogs in a 29.