I just wanted to comment on something that i have noticed happen in my tanks and i'm sure happens to everybody. It's more of a psychological thing than a physical thing with the tanks. As i have gone through the years, i have upgraded my lighting many times over my 29g tank. The first was an upgrade from a 20w 2500k bulb to a 20w 6500k bulb, and i immediately noticed the difference. However, after a while, it seemed as though the new bulb was getting dim, to the point that it was similar in color to the 2500k (this wasn't because the bulb was old, though). I then upgraded to 65w, and i thought that my fish were gonna get sunburn, since it was so bright. However over time, i have gotten used to the 65w 6500k light, and now mentally think it looks not much brighter than my original 20w 2500k bulb did. Obviously that's not true, so that's what i refer to as the darkening effect. Do y'all have a similar thing happen to you?