# Will spiral screw-in CFLs work?



## marky1991

I have a 20" high tank and I am currently using three 27W spiral screw-in compact fluorescent bulbs to light the tank. I know that these spiral bulbs lose strength due to the restrike. What kind of plants do you guys think I can grow with this lighting? 

Thanks


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## Logan's Daddy

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so yes you can, getting the right color spectrum (around 6500+k) is important though to help ward off algae.
What size is the tank in gallons? at 20" high the spiral bulbs won't be very effective near the bottom so high-light groundcovers like hc are probably out, but you should be able to grow a variety of plants under that lighting.


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## Sunstar

marky1991 said:


> I have a 20" high tank and I am currently using three 27W spiral screw-in compact fluorescent bulbs to light the tank. I know that these spiral bulbs lose strength due to the restrike. What kind of plants do you guys think I can grow with this lighting?
> 
> Thanks


Pardon my ignorance, what do you mean by restrike?


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## freydo

re-strike refers to lights that require time to re-light if they are turned off intentionally or due to power failure or brown out. all bulbs are affected by this to varying degress.


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## marky1991

Wai, now I feel stupid; isn't restrike when some of the light from the bulb gets absorbed by the bulb itself? 

@Logan's Daddy: Sorry, I meant it's a 20 gallon high tank. It's dimensions are 24X12X16 inches. Wow! That's alot of lights! By the way, I currently have two bulbs around 6500K and one at 2700K. After installing these lights, I developed (and still have) green water, and my GDA (even after the recommended 2-3 week period) is still very healthy. Should I remove the 2700K bulb? I put it in to help the plants as much as possible, but if it's going to cause further algae, I'll take it out. Do you think I have too much lighting? What do you guess my WPG would be?

Thanks


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## PRJCT92EH2

Marky you are correct on the meaning of restrike. There is a term for what freydo mentioned where the bulbs have to "warm up" but i can't remember it right now.

I would definately take out that 2700K bulb and replace it with a 6500K one. I am using two 13W 6500K bulbs in my 10 gallon and have hardly any algae and am growing a couple type of Ludwigia and chain sword well with only a splash on Flourish every now and then.


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## Logan's Daddy

Couple of things, "restrike" is indeed the amount of time it takes a bulb to relight once extinguished. However, many people in the fishkeeping world also use it as a term to describe the light that is lost due to being reflected back into the bulb it originated from, so you're both right. 

With a spiral CFL you lose approximately 1/3 of the wattage to this type of restrike.

SO:
with 3 bulbs at 27w each you have a total wattage of 81. Minus (about) 1/3 for the restrike issue you end up with 54 effective watts.

54 watts over a 20 gallon tank works out to 2.7 WPG. Fairly high light, if you are not running at least DIY co2 you will have constant algae, I would be willing to wager you would have just fine growth if you completely remove one bulb and just run with two. And co2 or flourish for sure.

Either way, you definitely want to get rid of the 2700k bulb, it is not helping anything but the green water.


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## marky1991

Okay, Thank you.


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## freydo

this is why T5 bulbs are more efficient that the sprial bulbs, the smaller diameter reduces the amount of lighting reflected back onto the lamp.


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## plurmaster

Im using spiral cfl bulbs from homedepot for 3 of my tanks and it works great plus is cheap. really helps cutting cost!!


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## xpirtdesign

considering using the spirals for my 10 gallon


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## jburn

I plan to use 2 or 3 of these over a 10 & 5 gal side by side with 20 watt spirals.


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