as of right now i have a t12 36" 30w 5000k bulb in my 30L.. i just put in a 18" t8 on my 10g.. the difference is incredible... ive also been looking around and i found some t12s 30w 12000K and 20000K but i dont know if they are any good.. now im wondering if i should swap out my t12 for a t8... what do you guys think.. they will both eventually have plants in them...
t8 vs t12
- Thread starter anonymousadrian
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I have a reg. fluoro over my 30, its just not enough light for plants. Its the big kind, can't remember which one that is. I pulled the guts out of a 4' fixture for my 55 and put in 2x55 CF from AH Supply, now thats some nice lighting. I'm hoping to slowly start switching all my tanks over to those lights. As for the difference between t8 and t12, you use the same ballast for both, right? So even if it looks a little different, you're not really increasing the output appreciably. Also, 6500K is a good temp to shoot for when looking for plant bulbs...those higher numbers are too blue, so even if they look just as bright, they don't put out as much usable light for the plants because its the wrong wavelength.
sploke said:
I would disagree with this. I put brand new T12 bulbs into my fixture and it looked dim compared to T8 bulbs that were about 8 months old. When I say dim, I mean there was a big difference between the two to my eyes.
The reason the output increases is that a similar amount of light is coming from a smaller light source. The best analogy I can come up with is a flashlight. If you have the flashlight set to a wide spray of light then focus it to a more narrow beam, it will become a lot brighter. Or consider a 100 watt light bulb. Imagine if the same amount of light could come from a small LED. That LED would be extremely bright.
Right, but the net amount of light is still the same, regardless of the size of the bulb. So, if going to the smaller bulbs allows you to add additional bulbs, then you'll be able to actually add light....but if not, then you just have the same amount of light in a smaller package. Cool I guess, but not really an improvement.
Also, just because a light looks brighter to your eyes, does not mean there's more usable light for a planted tank. The wavelength of light that the human eye is most sensitive to, is not the optimal wavelength for a planted tank. So, two bulbs with the same wattage might not look equally bright if the Ks are different.
I've also noticed that in the plant and aquarium bulbs I have over my houseplants, in a period of less than a year they have noticeably changed hue. They put out a much pinker wavelength now, and do not look as bright as they once were. It doesn't take long for these bulbs to show signs of wear, especially when compared side by side to a brand new bulb.
Also, just because a light looks brighter to your eyes, does not mean there's more usable light for a planted tank. The wavelength of light that the human eye is most sensitive to, is not the optimal wavelength for a planted tank. So, two bulbs with the same wattage might not look equally bright if the Ks are different.
I've also noticed that in the plant and aquarium bulbs I have over my houseplants, in a period of less than a year they have noticeably changed hue. They put out a much pinker wavelength now, and do not look as bright as they once were. It doesn't take long for these bulbs to show signs of wear, especially when compared side by side to a brand new bulb.
so a t8 30 w bulb gives the same output as a t12 30 watt bulb? where did you find that you can use the t12 ballast for a t8, i belive the t8 uses a lower current.
i think you all are nuts. i have 2 48" T12 bulbs on my 20 long, and 2 18" T8 bulbs on my 10g, and the 20 is SO MUCH brighter than the 10.