# low light, medium light, hight light



## flowerfishs (Mar 26, 2009)

Hello! I have some questions regarding the light per gallon for a planted aquarium.

how many watts per gallon (PGA) are consider low light?
how many watts per gallon (PGA) are consider medium light?
how many watts per gallon (PGA) are consider high light?

I use 49 watts light in my 20 gallon tank. It's 2.4 Watt per gallon. 
is that consider medium light?


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## supersmirky (Oct 22, 2008)

Hi Flower

Sorry nobody answered sooner.

Here is a guideline:

Low Light ( Under 2 wpg) 10-12 hours a day
Medium Light (2.0 – 3.0 wpg) 8-10 hours a day
High Light ( 3.0 – 4.0 wpg) 7-8 hours a day
Very High Light (4+ wpg) 6 hours a day

Suggested lighting periods:

2.0 Wpg 12 hours
2.2 Wpg 11 hours
2.4 Wpg 10 hours
2.7 Wpg 9 hours
3.0 Wpg 8 hours
3.4 Wpg 7 hours
4.0 Wpg 6 hours


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## flowerfishs (Mar 26, 2009)

thanks...


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## surpera1 (Feb 18, 2009)

why the shorter duration for higher WPG ?


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## supersmirky (Oct 22, 2008)

With higher intensity / wattage, you might get algae issues.

With higher light, there is also higher plant uptake so you might also have to dose more fertz and up the CO2.


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## niko (Jan 28, 2004)

Also keep in mind that the light spectrum makes a big difference. You could grow the same high light plants under 3wpg or only under 1 wpg depending on the light bulbs you use.

Giesemann Midday T5HO are the only bulbs that allow you to have low wattage and extremely healthy growth from day 1. These bulbs are also sold under at least 2 different names. Maybe someone will chime in about the names, I don't remember them. I just buy the ones labeled Giesemann Midday.

All other bulbs could be grouped in a common group. They will grow plants fine but you need to combine them and usually use higher wattage.

Also what's as important as the quality of the light (note that I don't say "wattage") is the establishment of the tank. In a properly established tank you can grow medium and high light plants without CO2 and with very low light. As I said - Giesemann Midday bulbs are the only bulbs allowing you to do that from day 1. Many other bulbs can do the same but only if the tank has had at least 6 months to establish. Patience is the key in this approach. See for youself - read the comments under each one of these pictures:
http://picasaweb.google.com/ddasega/Mike#

--Nikolay


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## surpera1 (Feb 18, 2009)

i am having excellent results with my lighting - i have a 2x55 ahsupply and a 2x ODNO walmart shoplight driving 2 T12 plant & aquarium bulbs - i really cant complain about the $20 i have in the wm fixture - it puts out some good light - i lined it with the shiny side of tin foil and super glued it on in true diy spirit - hahahahahaha - i just use the T12 because they are readily available to me - if i could get the same thing in a T8 48 inch i would - but yeah - i hear that T5's are all the rage right now - i just crank lights , nutrients and especially CO2 - i can vouch for some time to get established - my tank really took off at the 2 month mark - i have a potting soil substrate


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