No, but hearing the word BLEACHING and Geisemann in the same sentance is like hearing ROLLS ROYCE and WATER PUMP FAILURE in the same sentance, or even SPRINGBOK RUGBY AND LOSING in one sentence...
My only thought can be this, although this is VERY unlikely to be honest.
Your tank was (old setup) quite yellowish right? I see you only had two "blue" lights, and four lower Kelvin lights.
You changed this with the two actinic range lights (VERY GOOD INVESTMENT THERE) and then even with the two midday 6000K tubes (no probs there)
BUT... My ONLY thought on this (IF IT IS IN FACT THE LIGHTS AND NOT ANOTHER FACTOR YOU MIGHT NOT EVEN KNOW ABOUT) are the Aquablue + tubes. They have 5 phosphor bands in them, of 20000K and 6000K mix. Thus giving you a whiter look. It MIGHT be that the corals liked your lower kalvin tubes that you had more. Although this is VERY unlikely IMO. Those geisemann combo's you have are the best there is IMO.
What corals are starting to bleach if I may ask?
I also stand in awe at this occurance!!!
Experts please help and advice?