Posted: Wed Mar 25, 2015 6:43 pm Re: Clueless on outdoor setups
I'm a little confused by what you mean by "supported tray"--are you talking about a DIY basking ramp, or something you would use for maintenance/turtle care?
A 150 gallon sounds a bit small for a stock tank pond, in my opinion, as it would overheat faster at Houston temperatures than would a 300 gallon. On that note, no matter what size you use, make sure your turtle will have shade access both under and above the waterline. While this seems like a silly detail, it's something that I overlooked when I did my pond...
The kind of filtration you use depends on whether you're going to just buy a filter (like Pondmaster or Tetra), or build one yourself. In my experience, it's simpler and cheaper to build a barrel filter from a plastic drum; these filters don't need to be hidden behind a door. And about the drain plug - they're known to be leaky, and shouldn't be tinkered with very much if at all. In fact, two of mine are sealed shut, and I bought a whole new PVC plug for my third one. If you need to drain the pond, it's easier to get a pump to lift the water out. Just as with indoor tanks, turtle pond filtration should still function at 2-3 times the volume of your pond. For instance, my filter pump works at 1000 GPH on a 300 gallon stock tank.
Finally, if your pond gets sunlight (which, as you noted, it should if it's housing a turtle), algae is going to be a problem. Be sure to buy a good UV sterilizer for your pond (I use the TotalPond UVC-9, for example). You also need to consider predator threats (i.e., birds or other creatures that will want to eat your turtle). Have you considered some kind of top barrier for your pond?