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Enough Light?

1051 Views 5 Replies 5 Participants Last post by  CrazyMidwesterner
I have a 50 gallon tank that is 36x18x18. I currently have a 48" shop light hanging from my ceiling about 5" over the tank. It has 2x40W GE Ecolux bulbs. This gives me about 1.6wpg. I read in Peter Hiscock's Encyclopedia of Aquarium Plants, that I would need between 1.5-2wpg of flourescent lighting. I have also read on the internet that I would need 3-5wpg. With the lighting I have now, I have had some good growth, but I wonder if I would upgrade the lighting I would better growth. I have also had some bad algae at times with this light. Can ayone help me out?
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I think what you've got is fine, but it would be considered a low-light tank. 2 x 40 = 80W. 80/50=1.6W/gal. Usually 2-3 would be medium light. Also, shop lights usually just have white paint on them for reflectors, which work great, but not as well as those shiny polished metal ones that a lot of aquarium lights have. Wouldn't hurt to get more light, and your algae issues are probably related.
More and better lighting would certainly help with growth. You want to stay under 2.5 wpg to avoid needing CO2 addition. If you're handy, the kits from AH Supply are a good way to go.
I have a 55 gallon I did totally DIY with shop lights. While it did end up working out, I'll never do it again, the end cost wasn't much cheaper than a decent fixture, and it ate a ton of my time.

You could also consider t5 fixtures, I just bought a Nova Extreme that I like an awful lot.

While the 2 bulb 36" fixture would keep you about the same wattage (2x39 watt bulbs) it will be better aligned to the tank in length, better reflector, and has some great bulbs available - one of my club members suggested Geismann bulbs, the 600k daylights, he swears by them and grows (and sells) some awesome plants.

They also make 4 bulb fixtures that'd give you the option for a higher light tank.

Check them out here, among other places:


(Be a little careful, most of these are stock with saltwater/acitinic bulbs.... I found it cheaper, but then realized I had a bulb I couldn't use. There are freshwater versions that come with planted tank bulbs, like one of those in the link above.)


1 1x96 watt retro kit from AHSupply will run you the same cost (Adding a bulb) as a stock freshwater 36" double t5 fixture. Less wattage from the t5, but I'm led to believe equivalent growth - and it is a fixture, aluminum housing, not a wood box to build yourself, so you have to add that cost to the AHSupply as well.
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I added another shop light with 2 GE daylight bulbs (6500K and 3000 lumens each). Within minutes of adding the new lights the plants began bubbling and haven't stopped since. I have been running DIY CO2. I now have 160W (3.2wpg) and 9800 lumens (196 lumens/g) which should be enough. Obviosly some of this light is lost. This light setup was also inexpensive. It was only $15 for each fixture and $18 for all the bulbs. I may switch to a whole new fixture when I have to replace the bulbs in a year.
Regular T-12's generally loose a lot of their output after about 6 months. I use T-12's as well so that is just something to be aware of. While they stay lit the actual light output is considerably less and your plants will tell you about it :)
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