I personally wouldn't risk it on anything other than sugar sand. I've heard it is very rare for them to last more than a year or so on anything hard. Also, they are not entirely photosynthetic and some people say you should feed them daily. I have two and feed them every other day.
It could be okay, they do deflate sometimes and others only open up when the lights are out. I would check at night to see if it is inflated at night. Sometimes if you feed them in the day, you can train them to open up in the day.