Going green...

J

Just5398

AC Members
Mar 13, 2007
170
0
0
I have my 20 gallon cycled since April and want to add live plants. Here's what I have, what do I need to make this work?

20 gallon high. I have the standard hood with an 18" 19 watt flor. tube. I went to the pet store and bought a Flora-Glo 15watt flor. tube. I don't like it because it makes everything yellow but that's beside the point and I will most likely bring it back. I don't know or understand what the "T8" means so if you guys go technical you will lose me completely. I also bought Leaf Zone by API.

Sooo, what changes do I need to make to make the plants happy and prosper??

Thank you so much!!!!!!!!!!
 
The T-rating on the bulb inidcates its size, in eighths of an inch. A T8 bulb is 8/8 of an inch in diameter, or 1". Likewise, a T12 bulb is 12/8", or 1.5" diameter. Narrower bulbs are more efficient because they have less restrike, that is, less light is reflected back into the bulb since it has less surface area.

Light spectrum is something you will want to look at. If the tank looks very yellowish, you probably have a bulb in the 3000K range. The optimum color temperature for plants is closer to 6500K, which will look less yellow to your eye.

One thing you'll have to elaborate on is the type of plants you want to keep. Different plants have different light and nutrient requirements. If you're planning on staying with a 19w bulb, your choices are going to be fairly limited as far as what will grow under low light like that.
 
Thank you, Matt, for not going technical on me. LOL The package does say 2,800K, I just don't know what that means either. I will be happy with low - mid light plants. Just something to make it look nicer.
How high of a wattage can I go without changing out the whole hood?
 
The K stands for kelvin, its a description of the color of the light bulb. As you have found, temps in the 3000K range are more yellow, when you get up to 6000-10,000K, the light is more white, closer to 14,000K gets bluish, and if you keep going you get into the purplish actinic bulbs used for corals.

Wattage is determined by the ballast, not the bulb, so you're going to be stuck with around 20w max without doing a retrofit of some sort, or buying a new hood. You could probably keep java fern, java and some of the other mosses, and probably some crypts, but you won't see huge growth.
 
just add those as another light fixture that sits next to the tank? It wouldn't be on top like the hood, right?
I saw those bulbs at Wal-mart.
 
does the kelvin affect plant growth or is that just the spectrum color that our eye sees? From what I've seen on-line I'm limited to basically a 15 watt bulb for what I can use just the kelvin number changes so no matter what I will always have around 1 watt of light per gallon, is that right?
The flour. tube that came with the hood is a 19 watt bulb, am I better off sticking with that bulb? It's an all-glass aquarium hood and bulb.
 
The kelvin has a measurable effect on the plant growth, but as stated before it depends on the plants in particular. Not to mention that the kelvin rating does not denote any particular wavelength spikes that might have been put into the bulb via particular phosphors. It's more indicative of the appearance of the light to your eye. Plants don't care a bit. They are only concerned with available wavelengths of light to absorb and use. Once again, every plant looks for different light - hence they are all different colors and shades. Whatever color you see on a plant - well, if you recall from science class, is the light they are reflecting. In other words, the light they aren't using.

For example you can buy a home store bulb rated at 6500k but that doesn't mean it has spikes or peaks in particularly beneficial wavelengths for photosynthesis. Now whether this really matters all that much is wide open for debate; there are schools of thought that swear by specialty bulbs with things like trichromatic phosphors (causing peaks in three key areas of photosynthetic wavelength) and others who say they get just as good growth with plain old 6500k daylight bulbs from Home Despot.

There are other considerations such as CRI (color rendering index) lumens (the actual brightness of a bulb - watts only measure how much power they consume, not necessarily how much usable light they produce) and as said before, restrike and efficiency. For example many people have reported markedly increased growth upon switching from larger diameter (t8 and t12) bulbs in higher wattage to normal output t5 bulbs in lower wattages. I personally found that my plants took off and got a lot greener when i went with one of those Coralife T5 Aqualights as a replacement for a T12 shop light. I stepped down from having a total of 80w output from the original fixture to a total of only 56w on the T5 and yet growth and plant health actually increased. Saving space, saving money, and yielding better results. In fact I am so sold on T5 now that I am looking into a high output T5 setup.

One good practice that people do if they have several bulbs is to mix up the kelvin ratings to guarantee they are covering a lot of the spectrum. That way what one bulb might lack, another will make up for. If I were a real nut and had available to me a rainbow of T5 bulbs, I would have a set up where the first lights to come on were very low K and warm - like a sunrise. Then would come the cooler temperatures, so forth and so on until all of the temps from about 3k to 8k were illuminated, then I would have the cooler ones begin to turn off one by one until all that is left on is the first very warm bulb (sunset!) I'm a nut. But I will do this one day. And results will be reported.

Hope this confuses you more! Happy planting.
 
Last edited:
You must log in or register to reply here.
AquariaCentral.com
Top Bottom