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Old 21-08-2003, 11:33 PM
Jim Seidman
 
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Default Algae Algae Algae

tose (LeighMo) wrote in message ...
The tank is not heavy planted only half of it is planted. About the light,
it is a big difference about 2.2wpg on 29G and 65G. When you get 2.2wpg on
65G is the same as 3.2 on 29G.


If that's true, then you have to increase your CO2. Get compressed CO2, use
larger batches, or reduce the turbulence in your tank.

But I'm not so sure that it's true. While the watts per gallon relationship
does break down with very large tanks, I wouldn't call a 65 gallon all that
large. Moreover, it's a very deep tank -- deeper than a 29 gallon, even deeper
than a 75 gallon. The deeper the tank, the more light you need. Your tank is
25 inches deep. It's awfully hard to light a tank that deep.


I agree with the difficulty in lighting a deep tank. But in general,
the watts per gallon relationship only holds for a fairly narrow
range. 3 W/g is insufficient for a 3 gallon tank, just as it's more
than you need for a 125 gallon.

There's a really interesting article that analyzes the lighting in
Takashi Amano's tanks. He finds that, in general, Amano's lighting
increases as the *square root* of the tank size. So doubling the
number of gallons only results in about a 40% increase in the amount
of light. The article is at
http://www.fitchfamily.com/lighting.html

He even includes a calculator showing the amount of lighting Amano
would probably use on a given size tank. For 65g, it says 155W (or 2.4
W/g). For 29g, it's 107W (or 3.7 W/g). So if you believe all this,
Almazick is actually slightly understating the lighting equivalence
between 29 and 65 gallon tanks.

- Jim