So there is the EYE HORTILUX.
There is the Agrosun Gold SPectrum which gives both blue and red spectrum. Still go with the EYE Hortilux?
Then there is the Agrosun Red SPectrum bulb.
Between this and a co2 system what do you think it will increase the yield by on 12 plants? I am currently just purchasing sparkling water for co2 control.
I can't speak on the agrosun bulbs. I've never used them. One thing about the Agrosun Gold, it's a big old MH bulb that wouldn't fit in my cooltube, so it's no good for me right off. The red looks good, but from what I understand the EYE's have blue spectrum in with the orange of the sodium, I don't know anything about red. I'm sure you can't go wrong with any of the three, as long as they fit in your enclosure/ cooltube.
As for co2, for it to make a real impact you have to have other components of your grow dialed in. It works best in higher temps, and if you suck air out of the room, it will suck most/ all of the co2 you are adding. I think co2 is what you add when everything else is perfect. To answer your question though... Cheap bulb will yeild less than Expensive bulb + co2 for sure. Can't say how much more you will get, but definitely more. As a total shot in the dark guess I would say 5-20% more yeild. But that's just coming out of my ass... don't quote me.
The most important thing to get a good yeild is having temps, nutes, humidity, light ammount and distance, airflow, medium all good. All those things being dialed will give you happy plants, and happy plants will give you good heavy buds. And of course a big determinant in yeild is strain. I've grown 2 plants, 2 different strains, same grow... same exact conditions and share of light... one gave me 10 oz. the other 4 oz. So strain matters a lot.