Lately I have been totally devoted to learning the needs of my scorpions, but before I had scorpions I had turtles. I currently have 8 yellow bellied sliders, 4 common mud turtles, and 1 white-lipped mud turtle. The first turtle I adopted was a rescue I call Early. She was found crossing a community college parking lot no bigger than a quarter. I was curious of turtles having never adopted one and so I took this one. I immediately went to petsmart and bought the 20 gallon water turtle tank kit. It worked well enough while I was researching how to provide Early with everything she needed to thrive but she quickly outgrew the 20 gallon. So a few months later I put her in a 75 gallon top fin tank, roughly half full with a turtle clean 75 filter. Reptiledirect.com has proven to be the best source for everything pet related that I've purchased while being able to wait a couple of days for delivery. If a bulb blows and I don't have a spare I have to go pay the steep markup at petsmart, otherwise I order things online from reptiledirect and generally try to keep spare bulbs, food and filter media.
As Early grew, she needed yet a larger tank and this presented a challenge to me. The next tank that I could get that would allow me some time before having to buy yet Another tank, was the 125 gallon at petsmart which was $600. There had to be a better way, and there was. I bought a 120 gallon pond liner from lowes, and an fx6 from ebay. I saved over $150 from buying the filter from ebay vs petsmart. Not long after this I felt like Early had lots of extra room, so I took in 5 more rescue sliders from a coworker whose son had found them in his back yard. They were tiny. I kept them in isolation in the old 75 gallon tank for 30 days and once they had grown enough that Early wouldn't hurt them while feeding I added them all to the pond liner. Now, again, I needed a larger tank.
What I use today is a 300 gallon stock tank from tractor supply for my sliders. I have a plith in the center with some landscaping stones to bask on as well as a ramp that leads up to what was once a work bench in my garage. I covered the work bench in the green outdoor grass-looking rug material, scattered some dry substrate on the surface and built 2 foot tall walls to keep the turtles inside the dry space and not falling onto the garage floor. Above the 300 gallon stock tank is the 120 gallon pond liner where the mud turtles live. I drilled holes in one end allowing the water to spill into the larger stock tank where the sliders live. The fx6 pulls water from the slider tank into the filter and releases it into a 90 gallon pond liner where I keep mangrove and duckweed. The water drains from the 90 gallon pond liner into the 120 gallon pond liner and finally back into the sliders' stock tank. This way the water temp, ph, nitrate-nitrite-amonia content is the same in all three tanks and much easier to manage.
Around the tanks I have placed plants, allowing the turtles some privacy. They bask a great deal more when they feel secure. Some of them will still dive into the water when they see me approach but there are some who are used to me now. Also, my garage faces west, so as the sun is setting I open both doors and the entire garage is blasted with natural light which my turtles take advantage of.
I will post pictures later, but a cell phone does the setup little justice.