I need help understanding lighting

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Discuss all topics related to freshwater and planted tanks.


evnsmm05
 
Posts: 6
Joined: Mon Aug 06, 2012 1:47 pm

I need help understanding lighting

by evnsmm05

I want to have a planted tank any I am so confused when it comes to living I have read and read about lighting but it just isn't clicking. I have a 39 gallon and I am still working on the cycling process but I am looking at plants now to be prepared :) I currently have a 24" 17w T8 flora sun light in. Is that lighting ok or do I need something more? Thank you for your help!


natalie265
Site Admin
 
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Joined: Sat Nov 01, 2008 9:48 pm

Re: I need help understanding lighting

by natalie265

It depends on whether you want a high tech tank or a low tech tank. For a high tech tank, you need at least 3 watts per gallon, CO2 and lots of fertilizers. A high tech tank takes a lot more maintenance, but you have many more plants to choose from. On the other hand, you can have a very nice low tech tank without expensive lighting, but you have to be more careful in your plant selection. Check out Alasse's tanks which i believe are all low tech and look as good as most high tech tanks:

http://www.ratemyfishtank.com/friendemail.php/37224


Okiimiru
 
Posts: 275
Joined: Thu Feb 05, 2009 10:19 pm

Re: I need help understanding lighting

by Okiimiru

You don't need to wait until the bacteria are finished being established to add plants. To quote Diana Walstad from http://theaquariumwiki.com/Plants_and_B ... Filtration ,
"Aquatic plants, then, are much more than ornaments or aquascaping tools. They remove ammonia from the water. Furthermore, they remove it within hours (Fig 1, Table 2). When setting up a planted tank, there is no need to wait 8 weeks to prevent ‘new tank syndrome’. (Nitrifying bacteria require several weeks to establish themselves in new tanks and make biological filtration fully functional.) Thus, I have several times set up a new tank with plants and fish all on the same day."

Watts per gallon is an inaccurate way of measuring the light in a tank. Watts are units of energy, the electricity that comes out of the outlet. Different lights are differently efficient. Incandescent bulbs are very inefficient, and the waste a lot of energy as heat. Fluorescent bulbs are more efficient and produce more light and less heat if given the same number of watts of energy. LED lights are the most efficient and produce even less heat and even more light. If you gave the same number of watts to incandescent, fluorescent, and LED lights you'd get very different brightnesses of light outwards. A better measurement of the light in the tank is the lumens per gallon. 'Lumens' are a unit like 'watts' or 'meters' or 'pounds'. Lumens measures light brightness. So lumens per gallon are a good measurement of the light brightness in a planted tank. In my own planted tank I have 100 lumens per gallon.

Plants eat light. They photosynthesize. But they can't eat all the colors of light. Green plants reflect green back instead of absorbing and eating it. They eat blue and red light. Here is a picture of the absorbance of chlorophyll: http://upload.wikimedia.org/wikipedia/c ... tra-en.svg
You'll see there are three main colors of light:
Blue, 400-500 nanometers, easily absorbed by chlorophyll and eaten by green plants.
Green, 500-600 nanometers, not absorbed by chlorophyll and not eaten by green plants.
Red, 600-700 nanometers, easily absorbed by chlorophyll and eaten by green plants. Not eaten by red plants. Red plants mostly eat blue light.
Some bulbs produce a wide range of of light wavelengths. Some bulbs only make tight peaks at very specific wavelengths and emit either very little or no light at other wavelengths. A 'white' light can be a wide range of colors or it can be only a few sharp peaks. It's impossible to say what your white light is composed of without looking at its spectrum. Diffraction gratings are $5 online or are built into some digital cameras. Here's a video that will show you how to use one: http://www.youtube.com/watch?v=c44-iiINuVE
It's easiest to go with a full spectrum bulb so that you can know for sure the bulb is producing light at all wavelengths (in all the colors) that the plant needs to eat. I myself use these bulbs: http://www.homedepot.com/h_d1/N-5yc1v/R ... DreIaMn3-M in this light fixture: http://www.homedepot.com/h_d1/N-5yc1v/R ... reId=10051 There's a $10 model at Walmart too but I couldn't find the link.
I've never used the Flora Sun bulb but if it's designed for plants it should produce lots of blue and red light.

I personally don't use CO2. It's helpful but certainly not necessary.

A nutritious substrate helps rooted aquatic plants grow. There are non-rooted plants like hornwort (ceratophyllum demersum), java fern, the various moss species (like java moss, singapore moss, flame moss), water lettuce, water hyacinth, azolla, duckweed, utricularia gibba, etc. But rooted species like to be able to get things like iron, calcium, magnesium, etc. So there are two options. You can either add fertilizer regularly or use a substrate the already has nutrients in it. Sand and gravel are pure silicon dioxide and need nutrients added. Soil capped in gravel, pure clay kitty litter, Fluorite(TM), EcoComplete(TM), etc are all nutrient rich alternatives to fertilization. I myself use pure clay kitty litter. Here is why: http://www.thekrib.com/Plants/Fertilize ... jamie.html

Yup, I think I've covered a lot of main points. Let me know if you have any specific questions.


natalie265
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Joined: Sat Nov 01, 2008 9:48 pm

Re: I need help understanding lighting

by natalie265

watts per gallon is just a general rule of thumb that applies to florescent bulbs.

Okiimiru, how do you figure out your lumens per gallon and what is considered high lighting?


Okiimiru
 
Posts: 275
Joined: Thu Feb 05, 2009 10:19 pm

Re: I need help understanding lighting

by Okiimiru

natalie265 wrote: "watts per gallon is just a general rule of thumb that applies to florescent bulbs. Okiimiru, how do you figure out your lumens per gallon and what is considered high lighting?"

The light bulb I have says how many lumens it produces. Here is its specifications sheet: http://www.homedepot.com/h_d1/N-5yc1v/R ... reId=10051
At 100 lumens per gallon of full spectrum T8 fluorescent light I have great plant growth, even red plants. If I have both Lithonia light fixtures turned on (200 lumens/gallon) the algae grows a lot. So I leave one light fixture turned off and have only 100 lumens/gallon.
I just rest the shop lights on top of my 4 foot long tank.
http://img.photobucket.com/albums/v415/ ... /015-3.jpg
http://img.photobucket.com/albums/v415/ ... /018-4.jpg
http://img.photobucket.com/albums/v415/ ... /016-4.jpg


natalie265
Site Admin
 
Posts: 746
Joined: Sat Nov 01, 2008 9:48 pm

Re: I need help understanding lighting

by natalie265

Thanks. I'll have to see if i can figure out what my bulbs are.


evnsmm05
 
Posts: 6
Joined: Mon Aug 06, 2012 1:47 pm

Re: I need help understanding lighting

by evnsmm05

I really do appreciate your help with the lighting I think I got it figured out ;). Thank you so much for your time and the links!

I need help understanding lighting

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