I am using mostly non-dimmable units over my tank, since the dimmables weren't available back then, and yes, they are just as powerful, however the color is the color. In other words, you can adjust the amount of white and blue to make your tank look exactly the way you want, whereas I cannot. Luckily, I like the color as it is. Also, I can't keep some LPS
happy under the fixtures at full strength, and I can't turn them down to accommodate.
Get the dimmable units.