# T5 and no CO2



## art_b (Sep 2, 2006)

I don't have CO2. I just use flourish excel. Would 2x39 watts T5 lights (78 watts total) be too much for a 50 gallon tank ? Does wpg still apply to the more intense T5 lights or is it just for T8 ?


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## davemonkey (Mar 29, 2008)

t-5's are much more efficient at delivering light to the plants (if you have good individual reflectors). WPG of t-5 will be a higher intensity than the same WPG of t-8, but I don't know by how much. 

The best advice would be from someone who has used t-8 and is now using t-5.

Can anyone share some experience with this?


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## pogopleco (Feb 17, 2009)

Yes. I have used both for a long time and I honestly don't think T5 is any better, I found that the T8 with a higher kelvin, the light reached the bottom of the tank and my plants grew well. And in the T8 tank i didn't have co2. T5 was far to hot, overpriced and unnecessary IMO. T5 IMO s no better than T8 if you have a good T8 set up. And I would only have T5 with CO2. T8 lighting is great for NON CO2 tanks.


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## Philosophos (Mar 1, 2009)

IMO the real question would be what the PAR level is in mmol for the bulbs you have, and maybe comparing a few spectrum plots of various bulbs. If you're really in to things, you could try to roughly assess PUR. If I were to take consensus from the opinions I've read, it would be too much. The physics behind it is more important though; if you can figure that out, you have your answer.


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