12 bulb to led
shouldn't be to much of a stretch so questions first
What's your photoperiod ?
How far above the tank are the LEDs ?
90 or 120 degree lenses ?
My personal experience a with switching to LEDs was not as bad but I was only, and am still primarily doing soft corals, I started at @ 30 percent on the whites and blues and every 7-10 days bumped it up about 5 percent without much issue. The only thing I have noticed is a sight diatom out break for 2-3 days after upping the percentages and then it would just disappear.
My two tad are @ 9" above my 24" deep 65 gallon.
They have the 120 degree lenses.
And my programmed photoperiod is scheduled like this
7:30 am 3 nightlight LEDs come on
8:30 am blues come on
9:30 am whites come on
8:30 pm whites go off
9:30 pm blues go off
10:30 pm night lights go off
The night lights on my units are much to bright to be considered night lights, as even only 3 at full power will get my corals opening up.
I found with the LEDs it's better to err on the side of caution maybe up them until you see your corals open slightly and leave it there for a week and then bump it 5% and wait another week. My lights have been up for months and I'm still only at around 80% on blues and 50% on whites