Indeed the information the lighting manufactures provide is actually worse then useless. In an earlier post I described how I replaced an $80.00 name brand strip light with a non branded semi DIY light. Using a digital camera I found that its efficiency (aquarium illumination DELIVERED per watt) was much higher then the more expensive product.
Its obvious that the bulb, reflector and the position of the light assembly are mutually dependent upon each other. Why buy a light on legs? Whoever is engineering these things must know that light intensity is subject to the inverse square law. More likely is that their reflectors were designed to deliver focused illumination when a broader distribution is needed. Cheaper to raise the light then redesign the reflector.
As some here may know... electric powered model aircraft are capable of astonishing performance. WHY? Because it was realized that the prop, motor, battery and airframe are mutually dependent upon each other. Some bright souls developed spread sheets which optimized the various components for a given performance object (speed, endurance, weight and so on.) If you can build the thing straight its going to fly as calculated!
The aquarium hobby recognizes the reality of this but give only lip service. What does "balanced tank" imply and how can it be achived? Surely the mechanics can be quantified.
The situation with filtration, tank lighting and dimensions in this hobby presents a similar inter dependence to model aircraft but any acceptance or even common realization of same is at best given lip service. There is little or not quantification of the performance variables let alone their publication. Surely a manufacturer of strip lights could provide information on the angular distribution and efficiency of their reflectors. In reality most seem to avoid confessing the presence of one ! The only manufacturer who seems to spend money on development is Hagen/Fluval whose latest series of HOB filters are wonderfully engineered.
There are a lot more people keeping fish then building model planes but they just muddle along relying on anecdotal opinions.
Of course a model airplane has to be well engineered or it won't fly. Not the case with mass market aquariums which torture there unfortunate occupants to a lingering death.
Again Hagen seems to recognize the interdependence of the mechanical systems and their expanding line of purpose built tanks may point to the future. I see these tanks on display at the mass market stores. Hopefully they represent where this hobby is going.