I am looking to upgrade my lights and as I am investigating and reading the vast amounts of threads about them there is one concept that confuses me. I often read suggestions from reefers have some of the more expensive and or powerful lights that they do not have the lights fully ramped up. Often they quote as keeping them at only xx percentage of power. This confuses me because then why do we need such a powerful light? Is it another issue with the light such as general brightness etc? Because why would I need to buy a light that produces say 800 PAR at 12 inches when all I going to do is tune it down when I can save money and buy a light that produces the same amount of PAR at the tuned down PAR. Hope my question makes sense. I just want to fully understand all points before I make my next purchase.