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Re: Light intensity

> Date: Mon, 10 Jul 2000 16:58:43 -0800
> From: "Thomas Barr" <tcbiii at earthlink_net>
>
> Do you use the Dupla pendant lights also?

No, we have two 100g tanks with 4x40 watt fluorescent bulbs in enclosded hoods 
and a 120g tank with a 2x175 watt metal halide fixture from Hamilton suspended 
14" above the tank.

OK, True Confessions time. We really use very little actual Dupla equipment. We 
use the heating cables (cables only) because of the high quality and the bother 
involved with making something equivalent.  Our original 90 gallon tank had a 
Dupla transformer and temp controller since That Fish Place was dropping the 
Dupla line in 1990 and we got the pieces at 70% off retail. Our other tanks use 
DIY power supplies and UltraLife controllers. Our CO2 stuff is all DIY except 
for Sandpoint (RIP) controllers. OK, we do use Dupla CO2 reactors and bubble 
counters (there wasn't much else available at the time). Our trickle filters are 
Amiracle (made in Denver, I think). The only other Dupla stuff we use is 
Duplaplant tablets and Duplaplant-24 drops for fertilizer (which is a struggle 
to get).    

We have not established a new tank since 1995. If we did, we would try Fluorite. 

New subject:
 
As I've been reading the APD for lo these many years, one thing has been bugging 
me - the amount of light people use. FAQs and Urban Myths generally recommend 
"2-3 watts per gallon", a relatively crude measure that attempts to compensate 
for potentially poor quality FL bulbs (like shop lights with crummy lumens per 
watt and spectrum) and potentially marginal hoods with poor or no reflectors 
(such as come with aquariums). 

I've been hugely successful with 1.6 watts per gallon of FL light using Triton 
and Penn Plax Ultra Tri-Lux bulbs in fixtures with typical reflectors placed 
about 4" above the water. And thesea re 48" bulbs in a 60" tank! Since the MH 
bulbs in the 120 are suspended above the water, the amount of light at the water 
surface is the same as in the FL tanks (15,000 lux) and is not really like "2.9 
watts/gal". 

As I read some of the posts that mention algae problems, I am boggled at the 
amount of light being used. One gentleman wrote me and had 110 watts (CF) over a 
20 gallon tank. Holy Over Exposure, Batman!

I would like to see a discussion on two topics: 

1) What level of lighting do the experts use (Tom, Roger, Neil, Karen, Erik, 
Diana, Charley, Jon, ... you know who you are)?

2) Why do many of you think "more is better"?  IMHO, more is never better. More 
is trouble. Just enough is better.  
 

George Booth in Ft. Collins, Colorado (booth at frii_com)
  http://www.frii.com/~booth/AquaticConcepts