# [APD] Fw: Welcome to the "Aquatic-Plants" mailing list (Digest mode)-- or- I write em, U read em, erratum

```Oops. I dropped the decimal one place too far over. 200 liters, of course, is about 50 gallons (us).

2 x 40 =80 watts

80 watts / 50.28 gallons = 1.5 wpg

Fine for very slow growth and doesn't require added CO2 based on the rules of thumb I, and many others, recommend.

Target lighting levels -- Rules of Thumb"

wpg      =      watts/liter
slow growth        1.5                 0.3963
moderate            2                   0.5284
fast growth         3                    0.7926
faster growth      4                    1.0568

sh

PS: "reated watts" is the same thing as "rated watts" but with an extra "e". ;-)

Rated watts is the value of the manufacturer proclaims for the bulb, as opposed to what a particular unit actually consumes on a particular power circuit with a particluar ballast.

----- Forwarded Message ----
From: S. Hieber <shieber at yahoo_com>
To: aquatic plants digest <aquatic-plants at actwin_com>
Sent: Friday, January 27, 2006 1:21:15 PM
Subject: Re: [APD] Welcome to the "Aquatic-Plants" mailing list (Digest mode)

Oh, what Imeant was watts per gallon, which means watts/gallon. Aquarium volume is the denominator and rated bulb watts is the numerator.

If the example is 80 watts over a 200 liter aquarium, that equates to about 80 watts per 5.284 gallons, which equates to about 15 watts per gallon.

80 watts over a 5 gallon tank is a lot of light.

If it was a 200 gallon aquarium, that would be less than half a wpg; 80n watts is not a lot over 200 gallon aquarium, in fact, it's downright dim.

Scott H.

* * * * * * * * * * * It's new; it's fun; it's the New England Aquatic Plant Society NEAPS, is a newly formed organization interested in aquarium flora and fauna. http://www.ne-aquaticplants.com/

----- Original Message ----
From: Stuart Halliday <stuart at stuarthalliday_com>
To: aquatic plants digest <aquatic-plants at actwin_com>
Sent: Friday, January 27, 2006 12:35:17 PM
Subject: Re: [APD] Welcome to the "Aquatic-Plants" mailing list (Digest mode)

I believe S. Hieber wrote this email section below:
> Wise comments, but I will eleaborate a bit more.:
>
> "Watts per gallon" is a technique for estimating lighting levels. You
> take the reated watts of the bulbs over an aquarium and divide by the
> nominal volume of hte tank. The estimated watts-per-gallon that you
> compute this way allows you to work towards a target level of lighting.
> What's the target? There are diff ones depending on goals, plants,
> conditons, variations in equipment and gardening techniques. But these
> rules of thumb will serve just abut everyone well.

Gosh.

I've got a 200L tank with 2x 40W bulbs so that works out at

80/200 = 0.4!

sure you don't mean 200/80? Cause that makes 2.5
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