Backround: I have a small pond in Dayton, OH, 250 gal., 24 ins. at it's deepest, waterfall with bio-filtration, 1500gph pump, water heated to 50F during winter months, water tested regularly for pH, ammonia, nitrite, and salt levels, plants and Koi have done well for over 2 years.
The problem: Last summer we purchased 2 red eared sliders (at the pet store's suggestion) for the pond. They did well till fall and died. Web research told me that that turtle required a temp. range of 75-85F. This year we purchased 2 painted turtles from a different pet store, one lasted 8 and the other 10 days. We never did see them eat during the time we had them. The pet store told us our water pH at 9 is too high for turtles. I have not been able to confirm this. We purchased painted turtles as they are native to Ohio.
Are we doing something wrong? Is there a better suited turtle to this environment? Any help would be appreciated.
Dave

Red-eared sliders can overwinter down to near freezing. With your pond heated, they should have been okay assuming they got enough oxygen (aeration). You really run a 1500 gph pump on a 250 gallon pond? That's a lot!

A pH of 9.0 is too high for a lot of pond fish. It's not great for the painted turtles either but I don't think it should have killed them. Did they show any symptoms aside from not eating and being dead? I do suggest you try to get your pH down to 7 to 8. Is the high pH from your tap water or is there leaching, etc. going on in the pond like from cement?

I'm not sure what happened. My page on turtle ponds is at http://www.fishpondinfo.com/turpond.htm

I dont know about living up in Ohio or places that get cold, but down here in Southeast Texas, keeping turtles over winter is nothing. We have a few freezing nights in the winter, but RES are wild here. During the winter, I hardly ever see my RES, this past winter he stayed under the water, snuggled in the leaves most of the time. on really cold nights, i try and put a heat lamp by his basking rock.