A Green Filter? You're Kidding, Right??!!

I am heading out to a local spring fed lake to shoot a few pics of some checkout dives with a friend of mine who is a dive instructor. In a casual conversation with some divers at my job, someone suggested that shooting in a lake is not like shooting in the ocean. Sure, that is a given... But then he went on to say I should use a green filter for shooting in a lake instead of a red filter for shooting in the ocean...

Please tell me he was kidding!!!

I understand that red filters comp for the loss of red, but why would I dive in a lake with a green filter??!!

Does he know something I don't or should I tell him to 'put away the Crack before the Crack puts him away'!!!

I fail to see how a green filter would help in this situation. I think what your friend meant to say was that, in general, lake water has a greener tint to it than ocean water, which is "blue". There are filters for both "blue" and "green" water, but both versions are orangish-red. See:

UR-Pro

Mike