What is the best lighting for my aquarium?
by Aquaboy on Sunday, March 28th, 2010 | 4 Comments
I have a 29 gallon aquarium that takes a 24” T8 flourescent light. I’m not sure what any of the aquarium lighting vocabulary means like “kelvin”, “T8″, and like “WPG” because I am new to planted tanks. I was just wondering if anybody can suggest a specific brand and type of light I can use in my tank. I would really like something that could be considered “high light”. Thanks
The type and intensity of lighting in an aquarium affects health, stress, coloration, photosynthesis, and stimulates reproduction, among other things.
Some aquarium organisms come from shaded regions, like rain forest rivers, where most of the light in their day is indirect. These organisms do not require intense day lighting and some even fare poorly if subjected to it (e.g. mushroom anemones). These types of organisms may not need a full 12 hours of daylight.
Then there are high light organisms. These guys tend to come from shallow tropical areas where water clarity is sublime and they are bathed with intense, full spectrum lighting from the sun for 12 hours a day. These organisms have adapted to these conditions and some do not just flourish best under intense lighting, but require it to live (e.g. Tridacna Clams). Most coral reefs grow in shallow waters like this. Aquatic plants need intense lighting as well.
“Actinic light” is important to reef organisms and deep water fishes. Actinic lights produce UV wavelengths at the blue end of the daylight spectrum, which penetrates water the furthest and is most easily absorbed by corals and invertebrates. It is crucial to corals that rely on symbiotic algae (Zooxanthellae) that use UV light for photosynthesis. Actinic lights are not very intense and appear blue, so actinic fixtures also include daylight spectrum lighting.
You need a bulb in the 6,000k range for a tropical planted tank. i’m not 100% sure but i think 5 and above wpg, watts per gallon, is considered high lighting. you have a 29 gallon tank so you need 145watts. just google “lighting for aquarium” and you’ll get tons of sites for aquarium lights. make sure you don’t buy a bulb that your fixture cant handle. if your fixture says 30 watt max. then don’t just put a bigger bulb in it. you need to buy a whole new fixture. t5 and t8 are a measurement for the light. that really doesn’t matter if you are buying a whole new fixture. if you’re just replacing a bulb, you lamp will have a number on it ex. f15 t8 18. f= fluorescent 15= bulb wattage t8=size of bulb 18=length of bulb. Hope this helps
Kelvin is another name for color temperature. It’s used for a scale of the color of strs among other things. The hotter a star is, the *bluer* it will burn. The cooler it burns, the more red it will appear. You want a color temperature that’s close to natural sunlight, or 6,000K-7,000K. Look for a number in this range on the package the tube comes in [you can get a plant light specifically for growing plants, but these look a little too *purple* for most people's tastes]. It can make your fish look an odd color. Or, if you can find a tube that fits your hood, get 1 that says full spectrum.
T8 is just the diameter of the tubes that fit your light. If you multiply the number after the T by 1/8, that’s the diameter of the tube in inches. So a T8′s diameter is 8 x 1/8 = 1 inch. A T12′s diameter is 12 x 1/8 = 1 1/2 inches. The smaller the number after the T, the narrower the tube but the more light it gives off. Unfortunately, most hoods only use 1 wattage, so you can’t go from a 40w to a 65w without changing the entire light fixture. This is because fluorescent lights need a ballast to start them up, and the ballasts are rated for just 1 wattage of bulb. If you try to use a different wattage bulb, you can burn out the tubes in just a short time, and damage the light itself.
WPG is watts per gallon. This isn’t the best measurement to use, since there are different dimensions on some tanks – you can buy a 20 gallon tall or a 20 gallon long and although both have the same volume, the depths are different. The closer the light is to the plants, the more light they’ll get. It also matters if you hang the lights above the tank or just sit the light on a cover and how clear your water is. If there’s any discoloration from wood or dissolved organic material [these will tint your water brown] or any particles floating in the water, these will block some of the light. But for those who like the WPG measure, 2-3 watts per gallon is good for all but plants needing a high light level.
I personally use a double tube T-8 [shoplight] with full spectrum tubes. I have planted tanks set up on a rack, so the shoplights can light several tanks on the same shelf.
For a high light system for a 29g, you’ll need something like a double compact fluorescent such as
http://www.thatpetplace.com/pet/prod/209657/product.web
or a quad T5HO like
http://www.petsolutions.com/Sundial-T5HO+I42901150+C40001723.aspx
But since you’re a beginner, I would suggest that you try a low-mid light system like a single compact fluorescent
http://www.thatpetplace.com/pet/prod/209374/product.web
or a double T5HO
http://www.thatpetplace.com/pet/prod/236415/product.web
The reasoning here is because unless you’re growing plants that demand a lot of light, and add the appropriate amount of CO2 and fertilizers, the high light systems will simply waste a lot of electricity and grow a load of algae. With the other two systems I suggested, you’ll still be able to grow a lot of plants without being wasteful.