I've read all the threads about substrate and they haven't helped me much. I still don't know what to get. I know I want something the rays can bury in, yet I don't want anything really fine that can get sucked up in the python. I've read in all my stingray literature never use anything with silica yet I read these threads and it seems a lot of people do. I went to my LFS and the guy recommended natural ocean I think it was called. It was dry sand straight from the beach (for home aquarium use). Would this have traces of salt in it and if so is this ok? Can someone that has had stingrays for a long time please tell me a few substrates (the brand so I know how to order it)that the rays like and that is ok for them. I think there is a lot of misumderstanding about this among the newbies on the forum and we need some help taking the guess-work out. Thanks in advance!