# T5 vs T8, two choices for low-tech tank



## lljdma06 (Sep 11, 2005)

This has probably been asked a gazillion times. I have a 20g High (24x12xnot sure on height, between 15-18 inches maybe). I am doing a low-tech tank and have these options for lighting.

A. 1, 28W (2 14W) T5 24" Coralife fixture, giving me 1.4WPG

B. 1, 30W (2 15W) 24" T8 Fixture, giving me 1.5WPG.

Color temperature is about the same, 6500-6700K. The T5 has slightly less WPG, but will they be more efficient? Both fixtures have reflectors and have cost me nothing. 

Thanks,

lljdma06


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## czado (May 26, 2005)

Using Lumens/watt and Lumens/sq in , the "average" bulb, and 100% (or close) reflection, here are your lighting levels:

```
Eq T12 wpg    Lumens    Lumens/sq in
28w T5        2.47    2912    10.11
30w T8        2.32    2733     9.49
```
 Since wpg breaks over small tanks, lumens sq/in is the more important value, and you can compare these results to other established tanks here. Either light should work without needing CO2, but 1)T5 should give slightly more light.


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## lljdma06 (Sep 11, 2005)

Thank you very much for taking the time to answer my question, very interesting to know. I had a feeling the t5s would be better despite the lower wattage.

Have a great day,

llj


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