# Enough light for my 77 gal. PT?



## andy_mac (Apr 3, 2006)

Hello, I'm new to the site and am hoping somebody can judge my lighting set-up and tell me if it is adequate.

I've got 2 (56watt Twin-tube T-5's) from Corallife. 6700 K each.
Two 40 Watt Powerglow 18,000 K flouresent bulbs in my canopy.

My tank is 24" high and 48" wide. What do you think?

Thanks a lot


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## AaronT (Apr 26, 2004)

That is enough light for easier plants like Crypts, Anubias, mosses etc... The Coralife reflectors are likely not good enough to get strong light to the bottom of a tank that deep. Also, the 18,000k bulbs are not a good kelvin for plant growth. Try to get bulbs somewhere between 5,000k and 10,000k.


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## andy_mac (Apr 3, 2006)

Thanks for your input, would a third T-5 and one less canopy bulb help the situation or would you not bother?


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## hoppycalif (Apr 7, 2005)

If you change the 18000 K bulbs to 10000 I think you have enough light to grow most plants. Even the 18000 K bulbs may be ok, since those K ratings are not very real anyway. Unless the light from that bulb looks very bluish it is probably ok. Why not just try it and see? Unless you have some real low carpet like plants, HC for example, I expect you will be satisfied.


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## AaronT (Apr 26, 2004)

Adding another Coralife fixture would add plenty of light. The only concern I would have still is whether it would sufficiently reach the bottom of such a deep tank. The Coralife fixtures don't have the greatest reflectors in them. A fixture with parabolic reflectors will grealty increase the amount of light going into the tank and help to focus it deeper into the tank.


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## hoppycalif (Apr 7, 2005)

Just to be a contrarian, I guess, I don't think reflectors increase the effectiveness of light to penetrate to more depth. A reflector just captures the normally wasted light from the sides and back of the bulb and redirects it towards the water. Two feet of water does not aborb much light. And parabolic reflectors do not focus the light unless the bulb is very close to zero diameter. A parabola has a point focal point, and anything outside of that point is not focused, just redirected. 

Since we have debated the CO2 measurement process ad nauseum maybe we can have as much fun debating light reflectors?? I'm game!


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## andy_mac (Apr 3, 2006)

Thanks for the viewpoints guys! I added tinfoil to the roof of my canopy before I set it up, hope that helps. And I do have carpet plants. I've planted eleocharis parvula and e. acicularis (I think their the same thing) and I hope my light is adequate. I asked another hobbyist and he told my another T-5 would probably burn my high-growing plants. Do you agree? 

Thanks for dispelling the myth I heard that the more Kelvin output the better. I'll switch to plant-gro I think. Cheers
Andy


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