As for how LEDs work and the relations with PUR/PAR/CRI/Lumens....
It is all very confusing at times.
The higher an LED
is in k
(ie.17000k) the lower the par. This can be offset by adding blue. Blue LEDs pack a ton of PAR. Turn your AI white all the way down and your blues up. Check the PAR....then turns whites up and blues down and check. You will be suprised....
So, balancing good k
LEDs with the proper amount of blue is important....this is no different than MH
and t5 actinic supplements....It's all about preference...I personally don't like the smurf blue AI SOL tanks.
When you add lumens then it gets crazy. Lumens is what we see. This may not be good for corals necessarily BUT it is great for algaes.... This is in the 500nm to 650nm range which is where the 6500k LEDs put a lot of their light out at.
Very rarely do you see spectrographs for LEDs. The equipment is expensive and testing is very expensive. Our industry doesn't really generate enough business to make these manufacturers run out and perform expensive tests.
I dont suggest buying anything other than a good name brand fixture with LEDs that you trust. Anyone can produce these things nowadays. The $200 fixtures you see all over are very inconsistent. High quality LEDs are matched/batched and held to high standards. Lesser quality ones can be all over the field....They may look the same to our eyes but they aren't.
Think of lighting like this....do you add chemicals to your tank that you don't know about? (we try not to....)
So why would we put in light that we don't know about......