This thread inspired me to go buy a PVC unthreaded drain elbow, Ty! It was $.89 at the hardware store. 1 1/4 inches. It has a printed bar code on it that I am not sure I will be able to get off though. I am going to try it in one tank just to make sure it's really ok with my fish. I was first looking for decorations that would work out for a cave but everything I found was really super sharp inside. I didn't want to spend the money on something and find out I couldn't sand down the resin.
If the elbow works out, I plan on using the aquarium sealant to glue some of my aquarium gravel on it to cover the outside and possibly attach a silk plant to the bend. A big honking white chunk of PVC kind of clashes with a tank that is set up to look on the natural side to me lol. I am hoping the stones will make it less so. Thank you again for the inspiration you guys. :)