Questions about measuring WPG?

[genEus]

I have four 13W CFLs strung together atop of my 20gallon long tank. How much WPG is that? Is that 42W/20?

The CFLs say they have the same output as incandescent 60W, so is the WPG then 240W/20? Is it somewhere in between?

Should I not be worried about WPG but luminosity instead?

If so, what is, then, my luminosity? Overall, is 4x13W for a 20 gal shallow tank good? (I don't have CO2 but all my plants seem to be growing well, even Rotala Wallichii, which is supposedly a very difficult plant to grow)...

Thanks!

 

[msjinkzd]

You use the actual wattage, so you have just over 2wpg.

 

[jcardona1]

youre running 2.6 wpg. (13 x 4) / 20 = 2.6

That should be fine for your tank as long as they are within the right kelvin rating. just stick with 6500k lights and youll be good

 

[genEus]

youre running 2.6 wpg. (13 x 4) / 20 = 2.6

That should be fine for your tank as long as they are within the right kelvin rating. just stick with 6500k lights and youll be good

Wow. I'm embarrassed now! Couldn't even multiply 13 by 4. Yikes!

 

[jcardona1]