I decided to go with a sand substrate, I bought play sand and man it took a while to wash it all to get rid of the lighter stuff. It takes a lot of force to kick the sand up. It settles pretty quickly if it does though.
Since I'm using a wet/dry filter all the water is filtered before it hits my pump so I'm not worried.
This is a picture of my 35 gallon sump tank, I just bought a Mag 9.5, so I'm cycling the water about 10.5 times per hour, The tank has an internal overflow box that you can see in the pictures above. I had to drill it out to lower the water level.
Here is the best shot I could get of my turt, he wasn't being very cooperative.




