I'm putting together a non-CO2 20G tank and wanted to get some fairly inexpensive lighting for it. I bought a Coralife 2 x 18w T-5 lamp fixture. I could not choose the lamps it came with. One is a standard 6700K lamp and the other is a "Colormax Full-Spectrum Lamp with Color-enhancing Phosphors in the 350 to 750 nanometer range." This 2nd lamp is supposed to bring out the colors of fish and plants. I'm curious, though, will this 2nd lamp give useful light to my plants to help them grow? Since I'm going non-CO2, I'd be fine with just the 18w from the 6700K lamp, but I'm just curious, in case I decide to use one of these fixtures for another tank in the future.

Do you think this fixture gives out 36w of useful light, as far as plant growth goes?

Yes, I think it would give 36 watts of effective light. 350 to 750 nanometer is about the range of visible light.

Thanks for responding, Hoppy. The light is pinkish in color. I'll be interested to see if fish and plant colors do stand out.

The GE9325K bulbs are a pink-violet color too, but after awhile they look white. Our eyes quickly conpensate for unusual colored lights. But those bulbs really make the reds in plants and fish stand out.

I have a 10,000K AquaGlo and it does bring out reds in fish and plants (ha! if I could keep red plants alive) very nicely. I use that in combo with a Walmart brand 6500K daylight bulb. Works great.