Lighting requirements for Swords


I have 2 Amazon Swords, 2 Anubias Nana, and 1 Apong something......(forgot the spelling) My tank is 20 gallons and I have a deluxe hood with a glass canopy and my light strip only contains one florescent light bulb.

I read that Swords like moderate to high light levels, about 2 watts per gallon or (5000 to 7000 degress Kelvin). I went to Drs.Foster and Smith's site and ordered a bulb I thought would work. It had 9300 some degrees K, but it was still a 20 watt bulb. I realized I ordered the wrong size and needed the 18" bulb (I hope that's right, anyway) so I called and had them change my order. Then I noticed the 18" bulbs are only 15 watts. So I called back again, confused.

I *think* I finally found what I needed. She recommended the compact Flourescent 24". (My tank is 23 1/2" long). Here's what it looks like.

Does that look like it'd be good enough? Or is there something else anyone recommends to get the right amount of lighting I need for my plants?


To clarify: Kelvin temperatures on lightbulbs are the COLOR they make. It has little to do with the approximate wattage produced.

The fixture you linked to would do fine. The plants would get about 3 WPG. Some people recommend adding CO2 and dosing with different fertilizers at that light level, but you should be fine. You might get a little algae, but it shouldn't become a problem.


Anubias are low light plants and will do OK even under 1 wpg (I think), but Amazon Swords and Aponogetons need at least medium lighting (1.5 wpg would be enough). If you have more than 2 wpg of lighting, it's recommended to have CO2 injections in such a tank. And anything below 2.0 but above 1.0 - 1.5 wpg usually requires good substrate and/or some plant fertilizer but no CO2 injections. Or so I have been told on Plant Geek (plant geek).

As Marc has already explained, Kelvins tell you about the color of the bulb, not its wattage. For a planted tank, try not to have a bulb that goes above 10,000K as bulbs with 10,000K and above have a lot of blue color in them, and blue color encourages algae. In a planted tank the last thing you want are algae. I personally have 6,700K bulbs for my planted tank. I'd personally recommend something below 10,000K for a planted tank.


Ok, thanks for the clarifications. I'm glad I found the right lighting for them. I already have a CO2 diffuser so that's no problem either.

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