how much WPG do i have and Do I need CO2?

[JDogg]

ok first off, how much light do i REALLY have???

this is on my new 75 gal, do to reason longer then i want to get into right now the lighting i have is made up of a 40 watt NO fluorescent and 3 23 watt (100 watt Replacement) CF bulbs, one on each end of that tank above my swords, and one in the middle, give me a "even lighting" along the back.

so how much light do i have? 4.5 wpg? 1.5 wpg? 7 wpg?....

 

[Purrbox]

Hopefully czcz or Wizard~Of~Ozz will be along soon to give you the detailed analysis of your lighting. For the quick an dirty you've got a total of 109 watts. I'm counting the CF as a straight 23 watts even though compact flourescents give you better light than NO you're going to lose some of the benefit due to restrike caused by the spiral. This puts you right around 1.5 WPG and probably a nice Medium Low Light tank. You'll have a fair number of options with that much light, but CO2 is still going to be optional in all likelyhood.

 

[JDogg]

Hopefully czcz or Wizard~Of~Ozz will be along soon to give you the detailed analysis of your lighting. For the quick an dirty you've got a total of 109 watts. I'm counting the CF as a straight 23 watts even though compact flourescents give you better light than NO you're going to lose some of the benefit due to restrike caused by the spiral. This puts you right around 1.5 WPG and probably a nice Medium Low Light tank. You'll have a fair number of options with that much light, but CO2 is still going to be optional in all likelyhood.

the reason i am getting concerned is my fanwort and anarchari, both of which did fine (but grew slow) at 1.6 wpg in my 28 gal, but neither are doing well in my 75 gal.

 

[Purrbox]

It could be that there is just enough less light that you've crossed the threshold from where those plants can survive to where they can't.

 

[janek]

The 75g is probably deeper than the 29g. That would make a difference.

 

[malkore]

I say you have about 1wpg. 40w + 60w from the PC's, but divide by two due to restrike and inefficient design for aquarium use, yields 40+30=70w.