Yes, I recently switched to sand in my tank. I have had it for about 2 weeks.
Actually it is the cleanest substrate other than a bare bottom.The stuff sits on top and cannot get trapped beneath it because the sand is denser than waste. Anything not caught by the filter just gets netted out of the tank.
A word of caution when using sand, Make sure you wash it out extremely well, all sand has some dust that needs to be washed out and can take forever to settle if you don't. I washed mine for about 10-15 minutes until the water ran clear and then some. I still got a bit of cloudiness.
When sand is kicked up by the turtle, it settles very quickly as well. Make sure that the filter intake is about 3-4" above the sand so that if he kicks any up by the filter it won't suck any up.
The sand granules are so small that if a turtle eats it, they can pass it pretty easily. The risk of impaction is actually very low.
here is a couple photos of my tank with sand bottom:
Hope it helps, Any other questions, feel free to PM me, I'll be happy to answer any questions.