150+ Gallon Indoor Pond and Murf

Hey all, I'm a new guy who came here with iguana questions, but I thought I'd post some pics of my (pond or river, not really sure) cooter named Murf and his pond. He's about 18 or so, and his shell is 9 inches long. He almost died last winter so after he started showing signs of getting better from putting him on antibiotics, I decided to build him a new home. 2x4 construction, inside dimensions of 3x5, insulated, pond liner, Do-It-Yourself wet/dry trickle filter, MVB day and red night lights on a timer. Holds about 150 gallons when the water is 15" deep. He's a little fat in these pictures, we've since put him on a diet and he's not all "bloated" anymore. He's a hilarious little guy, he will follow you around if you walk around the pond and he goes nuts at feeding time.

Nice setup.
Now I'm not a turtle guy, but how can you tell when a turtle is overweight?

He is super cute! I love turtles

Awesome setup (wanna come build one for me?) Lucky turtle.

I have seen overweight turtles: often times, the only place for the fat to come out is in the leg-holes of the shell - it ends up looking like a fat roll, but wrapped around the leg (or puffed out when the leg is withdrawn into the shell)

Nice, I like the setup
Curious, what are you using Filtration wise?

Nice home he has there!

What did he almost die from? Animal attack?

He almost died because he caught some kind of infection last winter. He didn't eat for almost six months. His old tank was way too small and he had no UVB (I didn't even know reptiles needed UVB at that point, I mean he was already about 17 years old and had never been sick before!). He's doing fantastic now and it's easy to tell that he loves his new home.

I'll try to describe the filtration system - I spent a good amount of time designing it. There's a 1000GPH pump in the pond with a pre-filter that's plumbed into a diverter valve where most of the water just gets pumped back into the pond. Some of it is pumped up into the top of that blue rubbermaid container (that's the wet-dry biological trickle filter), the diverter valve controls the flow through it. The water goes through a PVC spray bar onto a layer of fiberglass insulation, then drips down through about 300 plastic pot scrubbers and out the two drain tubes in the bottom. There's also an overflow up higher just in case. I've also got a few pounds of crushed coral inside to help with the pH level. Then there's a connection where I can attach a garden hose, shut off the flow through the filter and use the pump to drain the pond (I can get the water down to about 4" deep before the pump starts to run dry). Makes partial water changes super easy.

It took about six weeks for the filter to cycle (I had high nitrite levels), but now that it has it's very stable. The water quality is excellent and I only have to the clean the prefilter and change the fiberglass filter about once every two months.