# new 30" light fixture for 29g tank - 1 65W CF vs 2 18W T5s



## gheitman (Aug 18, 2007)

I'm planning on setting up a new 29 gallon tank and haven't decided on what light fixture to get. I'm torn between the Coralife Freshwater Aqualight Deluxe Single 30" Strip with one 65W 6700K compact flourescent lamp and the Coralife F/W T-5 Aqualight Double Strip Light-30" with one 18W Colormax full spectrum and one 18W 6700K T-5 fluorescent lamp. The compact fluorescent fixture costs slightly more ($59.99 vs $36.99 at Big Al's). I want to plant this tank with Amazon swords and other South American plants and I'll be using a Filstar canister filter and injecting CO2 via fermentation. Which light fixture would you recommend and why?


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## SpeedEuphoria (Jul 9, 2008)

65w for sure, the other one is pretty low lighting for a 29g and would make CO2 pretty pointless IMO


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## Pyro (Nov 20, 2005)

I just upgraded from 1x65 watt to 2x65 watt because my ground cover plants seemed to struggle with just 1x65 (glosso mainly) and I got a good deal on a light fixture. With DIY CO2, you might want to just keep the 65 watts. Plants didn't do too badly, and with DIY CO2 which tends to be a bit unruly, 65 watts is probably your best bet. Even with pressurized CO2 and a full battery of ferts, I'm cringing a bit at how much something could go wrong with 130 watts of pure lighting power over a 29 gallon (~4.5 wpg)


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## The old man (Apr 12, 2008)

I agree. The 65watt should be just right.


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## thefishmanlives (Feb 15, 2008)

CO2 is never pointless and works quite well in low light setups. Produces lusher growth and keeps algae at bay. the 18x2 COralife aqualight T5 fixture puts out pretty good light. The 65x1 PC fixture with poor reflector would probably give around the same amount of light with either. WPG is NOT a good way to determine actual light that you get to the plants. T5 produces more light per watt the PC. No offense but im afraid this is poor advice. :icon_hang



SpeedEuphoria said:


> 65w for sure, the other one is pretty low lighting for a 29g and would make CO2 pretty pointless IMO


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## thefishmanlives (Feb 15, 2008)

With DIY co2 your asking for trouble with 13o watts, but with pressurized co2, its pretty easy to keep things under control with proper ferts, even for a newbie. I would actually recommend 65x2 instead of 65x1 with pressurized co2 especially if your talking about a coralife fixture with poor reflector. Your even good to go with a 65x2 with a good flector such as the AH supply, many people run that all day on here and run it smoothly. Ive run 65x2 over my 29 with no problems at all as long as I kept my co2 stable and ferts in check.  If you felt it was too much light you could always use the 2nd bulb as a few hour burst. Better to have more light on tap then not enough. Nowadays with the use of seachem excel, its very easy to keep algae at bay in high light setups even if your a little off with things here and there. Stable co2 is a must tho. Not really all that much can go wrong if you can follow simple instructions. Fertilize enough & co2 must be stable. Thats about it. :spy:



Pyro said:


> I just upgraded from 1x65 watt to 2x65 watt because my ground cover plants seemed to struggle with just 1x65 (glosso mainly) and I got a good deal on a light fixture. With DIY CO2, you might want to just keep the 65 watts. Plants didn't do too badly, and with DIY CO2 which tends to be a bit unruly, 65 watts is probably your best bet. Even with pressurized CO2 and a full battery of ferts, I'm cringing a bit at how much something could go wrong with 130 watts of pure lighting power over a 29 gallon (~4.5 wpg)


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## gheitman (Aug 18, 2007)

I've pretty much decided to go with the single 65W PC fixture (with pressurized CO2) as opposed to the dual 18W T-5 fixture when I get a new tank. I have two of the dual T-5 fixtures now over 30g and 20g long tanks and have been very satisified with them but I'm not sure I would get enough light in this case. I remember seeing a spreadsheet somewhere that allowed you to calculate the light in a tank depending on the type of fixture you used, the depth of the water, etc. I can't find that spreadsheet now. Does anyone know where it is?


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## gheitman (Aug 18, 2007)

I did get the 65W 6700K PC fixture with the adjustable legs and have set up the tank with the top open. I'm using fermented CO2 now but will change to pressurized CO2 sometime in the future. So far I really like the Coralife fixture I got. It appears to be well designed with small things like the power switch being sealed against moisture.


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## Brilliant (Jun 25, 2006)

I would buy the 2x18w fixture any day of the week. Dismissing the Aqualight T5 because of the lower wattage is foolish.


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## niko (Jan 28, 2004)

If you can DIY you could get a 24 watts Giesemann T5HO bulb. The results with only one of these bulbs (with an individual reflector) will equal if not surpass the CF.

If you have two of these bulbs over your tank you can grow anything you can imagine in that tank. Prunning will be a headache. 

-- Nikolay


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## HockiumGuru (May 2, 2008)

niko said:


> If you can DIY you could get a 24 watts Giesemann T5HO bulb. The results with only one of these bulbs (with an individual reflector) will equal if not surpass the CF.
> 
> If you have two of these bulbs over your tank you can grow anything you can imagine in that tank. Prunning will be a headache.
> 
> -- Nikolay


whats the difference between the CF and t5's (giesemann and aqualight) that makes 65w vs 24 or 36W so comparable?


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## Brilliant (Jun 25, 2006)

HockiumGuru said:


> whats the difference between the CF and t5's (giesemann and aqualight) that makes 65w vs 24 or 36W so comparable?


In this case 65w of CF is very inefficient. Most of the light is bounced around, between bulbs, atop of the tank or inside the fixture. The bulb lights the tank with brute force. The size of the bulb is actually its hindrance. Such a large bulb blocks reflected light. The CF bulb is good in applications like a nano where 27w quad style bulb provides much more light coverage because of the size of the bulb.

The Aqualight T5 fixture does not have a good reflector but provides similar light coverage with lower wattage bulbs. Lower wattage also means lower heat. The Aqualight T5 does not have or need a fan. Double bonus.

The 24w setup with individual reflector will provide almost identical lighting as the 2x18w fixture because of wide spread of reflected light concentrated downward on the tank. Check out my post here at APC for a picture.

Using watts per gallon will cloud your thinking. Think of it more as light output regardless of wattage.


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