Originally Posted by Caliban07
I read an interesting thread about attenuation coefficients or the exponential law of attenuation causing higher PAR intensities when the light travels through water. I always thought this would be the opposite (more intensity in air). Also there seems to be some evidence to support that you can quantify par and watts. Unfortunately, the scientific links provided no longer work. Definitely worth a bookmark though. I love these threads.
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Many thanks - that's all pretty interesting. I'll keep this to have a look through the links later.
I have noticed since lowering the light onto the tank I'm getting better pearling (which in my case is anything) across the tank. This is only a few inches lower so it could well be that it is just cutting out the reflection of the glass top and I can believe reflection can be quite significant inside/outside tank.
I'm convinced the catfish are having a go at the stems of the red alt at the base. Two floated up this week. The stems don't really look rotted and they seem to be doing better with several stems planted together.
So I'm thinking of getting some more and planting densely to stop catfish swimming through and head off some light algae growth in the stems near the substrate.