I just think it would be cool to use A CANNON.Great point Salty! That would be a fun experiment, essentially testing photoinhibition in clams. Problem is there are so many other variables. Once a person could keep all other variables constant, and just use light for the hypothesis, it would be cool. Of necessity one would also have to have a clam of the same type at every different level of the tank with known PAR levels, but it could be done by someone smarter than me.
I've seen I think it's an ecotech. Come up for sale a few times usually a few hundred bucks.