exactly, I believe its Magnesium Arsonate that is needed for the deep reds, and just like almost all other rare earth metals, it is mined and sourced almost exclusively in china, and they've been artificially inflating their price lately because they are also needed in manufacturing electrical components and alot of high tech stuff like ipods etc. Its been in the news that the International Trade Committee or some kinda international group that promotes trade/commerce is filing official complaints against China and is considering some kinda punishment like cancelling trade agreements or ending cooperation with China over it. Anyway, it is more expensive for the Red phosphors, it takes different combos of phosphors to create different colors. for all practical purposes, we can use these lights and count on their output being practically equal, but on a micro-physics level the longer Red wavelengths are not as powerful as the shorter Blue waves, the Blues cary more photonic energy. Through the visible spectrum, the difference isnt really too much (at least for our practical usage), where as the difference between UV and IR is a little more dramatic. In flower when you switch to a red spectrum, a little bit higher percentage needs to be dedicated to Red than Blue would be in Veg. This is due to the weaker Red waves that are needed dont carry quite as much energy so you need a little more Red to actually tip the balance towards the red end of the spectrum
Theres no tint on these bulbs, its a powdered phosphor compound that coats the inside of the tubes like a glaze, if there are spots that are a lighter shade or not the same hue (like on the ends) its prob from that area not getting an equal coating of the phosphor glaze. I dont think it should affect the time the bulb will last light, just the hue emitted in that area. Without that coating, the bulbs would emit Hazardous UVc, like germicidal lamps which are basically clear quartzglass fluoros. In our bulbs, the UVc created by the electrical current excites the phosphors to start glowing/emitting the desired colors... kinda similar to colored fireworks in a tube if ya think about it
