This is very interesting to me as I have MH and a deep tank (24").

I feel that since even leaves and Riccia at the very bottom of the tank pearl, I am 'okay', but now wonder what the growth would be like if the light intensity was that of the surface!

Anyhow, based on this, how to determine an 'optimal' height above the tank for the fixtures?

Can it even be done with all of the variables that could go into the equation?

Sorry, never got past HS algebra lol

Great info. Thanks for sharing!