Re: Lighting question

[Bill Wichers <billw at waveform_net>]

>I've seen references to the effect that lighting requirements are different if
>the tank is in excess of 22 inches in depth.  I need some clarification on 
>this.  Is the 22 inches from the water surface to the substrate or from the 
>light itself to the substrate or what???  If there is a different requirement 
>for depth over 22 inches, what is that requirement?


My understanding has always been that this is the distance from the surface
of the water to the top of the substrate. I think it is often interpreted
as the total height of the tank though as taken from the manufacturer's
specifications. The common figures given, at least for MH (not sure how the
others would work out) are 175w for up to 24" depth, 250 watt for up to
30-36" depth, and 400 watt for up to 48" depth. People vary the amounts to
get the level of lighting they want. I know the 175 watt MH fixtures will
do a good job in a 24" deep tank, and would probably be OK up to 36" for a
planted tank.

     -Bill

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Waveform Technology
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