that's what i'd guessed at, very well done. i've been looking for ways to keep my airstone tubing down, as with all the air in the tubing, they like to float and shift around and turn my airstones over. unfortunately, my tank is not bare bottom, nor glass, so siliconing is out of the question (zavlar liquid rubber). thinking i'll have to weigh them down some other way, maybe something heavy and harder for a ray to move, like a big rock lol
If you cant silicone it to the bottum ,take a thin pvc pipe fill it whit sand and close the ends.
Then use tyraps to connect it to the airhose , the hose will stay strait and on the bottum.
