Wonder water?

> From: bowkerg at NTU_EDU.AU (Gail Bowker)
> Date: Thu, 20 Jun 1996 10:16:11 +0930
> >One way to tell if this is photosynthesis or just trapped gas escaping
> >is to change water with the lights off.  No light, no photosynthesis!
> But, how could you see the bubbles if the lights were out?

It doesn't need to be very dark to stop photosynthesis.  Ambient room
lighting will not support [much, if any] photosynthesis unless, of
course, your ambient room is outdoors.

At the worst, you could sneak up on the tank and snap the lights on
for a few seconds to check for bubbles.  Or, HEY!, use a flashlight. 
Yeah, that's the ticket.