Lumens do not apply to plants. Period.
Lumens is the amount of light seen by the human eye. It has absolutely nothing to do with plants. Our eyes peak in the green spectrum of light. Some have probably noticed at one point, 2 lightbulbs of the same wattage may have different brightness. It would seem obvious that the brighter one would be better, however that is not always the case. This
is the spectrum we are able to see. Lumens again is a measure of the light visible to the human eye. Plants on the other hand reflect green light(they cannot use green light). Plants need light with peaks in the red, blue, and yellow spectrum. This
is the spectrum plants can use.
In general the spectrum we see and the spectrum plants depend on is almost opposite. So, picking bulbs based on lumen value is a very poor way to choose a bulb for plant growth. It is easy to determine, a green bulb is going to have a very high lumen rating, plants however will die under green light. So if you are lighting your house it would make sense to go for a bulb with a higher lumen rating. Plants on the otherhand may perfer bulbs with lower lumen rating. This bulb may look dimmer to us, but may indeed be more efficient for the plant.
So how to choose a bulb? There are many sites that list the reported PAR efficiency of specific brands of bulbs.(here
) PAR is a measure of the light that is usable in photosynthesis. If or when you are looking for new bulbs it is helpful to pick a bulb with a known high PAR rating. Since this is not know on most bulbs and is not list on the package of any, another way is to look a the bulbs color spectrum. Generally, the more closely to resembles the spectrum a plant uses the more efficient the bulb should be. Though this does not take in account the Kelvin rating or visual appearance. Its best to pick a bulb with a good spectrum and a ideal kelvin rating. Kelvin rating is dependent on the user though, it is whatever looks best to you.
So this is the spectrum a plant uses in general.
This is the spectrum PAR measures.
Here is the reported spectrum of your original Colormax lights, sometimes these are on the package, sometimes the internet, sometimes they don't exist (if you buy a cheap bulb).
This is my perfered bulb GE 9325K, it doesn't have a T5 version though, just PC and T8s.
This is the spectrum measured by lumen
Woot! Now I'm done, since I've probably bored you all. In the end light is very complex. If you ever bother to really go indepth with it, you will eventually figure that despite all the fancy fixtures we buy and specilized bulbs we use. Cheap spiral compacts will generally do the job just fine. They may not be as efficient, as t8's, t5, pc, ect.(depending on the bulb). Usually no spectrum, just a kelvin rating to go off of.