The deeper the tank, less light penetrates the water to make it to the
bottom, so are you asking how much light or how to plant without CO2?

How much light? just a guesstimate
40W minimum without CO2
60W with CO2

Deeper tanks lend themselves to rocks for backgrounds, maybe a shelf with
plants on top, maybe the top 1/3 of the tank could allow a 6-10" planting???
just a thought....
________________
| |
|___plants _______|
| X X |
| x |
| X X |
| |
|__X X X X _|

atleast that would be different... I dont' know what I'm thinking, just a
brain fart or something....







"JEB" wrote in message
om...
Couldn't wait any longer, so I went out and got a 20XH and would like
to plant it. Want to start out low tech (read: no CO2) and wonder if
anyone has a suggestion as to how much light I should put over it for
that. The hitch is the depth, about 24" from the bottom to the glass
hood. With 4" gravel, I'm looking at 20" of water, and don't know how
the depth factors into the light requirement.

Any suggestions?
thanks-

James