Hi,
Well, the efficiency of the unit is one thing and it's usefulness is another thing entirely. If we are concerned with the electricity bill and if that is a high priority then it's something we have to consider very carefully. However, one has to consider that high PAR in tanks is the prime factor which triggers massive algal blooms. So for example, a unit which generates twice as much or thrice as much PAR for the same wattage would cause many more headaches unless flow, distribution and CO2 were higher.
Despite the fact that Barr points out the inefficiency in the unit, one needs to look deeper into his analysis. What he is actually complaining about is not just the fact that the units are inefficient, but instead he is complaining about the worldwide propaganda which encourages the concept that high lighting is required for plants. He is stating that ADA support the propaganda, yet, at the same time their units are not really high light. He is complaining about the hypocrisy, not the fact that the unit produces low PAR, which is actually a good thing. He would prefer that ADA admit that excellent results can be obtained by using reduced intensity, and that they support that admission by revealing that their units produce a lower intensity. Can you not see that in the very same post?
...Whether this is on purpose, or trial and error on ADA's part.......I cannot say. It's often dangerous to try and out think marketing and public's desire for "more is better", particularly if someone like me bothers to to test the product only to find that it has a conservative rating of 2X worse PAR output as other brands using the same bulb. I guess if you tell folks enough baloney, they will believe and not check to see if what you say is true...
...they are supporting the myth that high light is required and to telling you why their's works so well...
Barr is himself telling you that the hysteria about high light is a myth. You don't need high light. You therefore do not need to run away from the ADA unit to find something that produces better efficiency. the lower PAR is better for you, but he simply wishes ADA would state that and not support the myth about high light.
When you understand this at a fundamental level you will see that the efficiency of the unit in-and-of-itself is not the relevant issue and that using a unit that has higher efficiency and which produces high PAR values will not serve you.
It's because people do not understand this very important concept about the relationship between PAR and plant health that they are easily sucked into the propaganda, and that is why many tanks fail while ADA and others continue the illusion of blaming phosphates and Nitrates for algal blooms when in fact alga results from high light. But if I tell you that I am using high light when in fact I am using low light then this is a distortion of the truth. And if I then tell you that my entire nutrient product range is based on enriching the substrate instead of enriching the water column to avoid algae then this is a further distortion of reality. If I then say that my light unit does not produce algae because of special magical or spectral properties, when actually it's simply because the unit produces a low PAR then this is an even more infuriating distortion of the truth.
Hope this clarifies.
Cheers,