The PAR is not low in other brand hoods, the bulbs are fine, but if you measure their hoods and + the bulbs, they are very low, maybe 2-3X less than you might expect based on PAR alone.
At least that is what I found using a PAR meter on 6 different ADA light systems.
Everyone was close to that range of being 2-3x less.
So it's not really the bulb it seems, it's their ballast and reflectors etc.
The marketing ADA "poetry" really conflicts with Defdac's notions about PUR vs PAR also. Not just his notions, but the general notion about PUR in general.
The only thing I can see is that they purposefully chose to reduce the light intensity so that folks would get slower growth, but less issues with a wider range of public dosing routines when using their brand of lights.
So more folks would have less algae and dosing issues with their lights, while others would have more hassle using other brands.
I do not think the bulbs factor into itthat much really, but more based on the person's asethetics of color. Most aquatic systems where plants are are not filters by trees, aquatic plants do not grow where there is a deep forest, they tend to grow in marshes, at least 90% of the aquatic plants species, some do, like Anubias and you will find some species in forest and marshes.
But in general, they live out in the open and the biggest filtering issue is that of the water itself. But most live in 1-2 meters max depth, so color filtering is not a large factor in most cases, rather, reflectance from the surface of the water for the first few hours and the last few.
Once the sun is high enough, you get good penatration at a decent angle.
I think the greener color is like using the hue filter in Photoshop you get greener coloration from the light to make the plants look greener than they really are in "true color". That, and not PUR is what they are really doig and marketing statements are just for sales. If they said it was really low PUR to wate light so folks would not add so much, thqt the bulbs just reflect the green color nicer etc, then it does not sound so good and few folks would buy it.
If that is not it, I am really sort of worried about how they go about things, because then it would suggest abject ignorance and poor testing. You could arrive at such a light set up based on some trial and error and never know "why" the light worked well etc, someone could even tell you etc why, but you may not care as long as it works and all you care about is scaping etc.
Why change it if it works for you and sales are good? So many simply do not care why it works, only that it does and they can make some $.
Could be that also.
Still, I get a bit suspicious of folks when they are not forthright about things.
If there's something I do not want to tell, say etc, I say so, "Nope, I am not telling you. Live with it".
Regards,
Tom Barr