what watt are the 12ks? and the 24 leds? I wonder if they were closed because they weren't getting enough light, you had mentioned some algae growth which could be from a light shift, and since it cured it's self shortly after adding the new light it could be a very good indicator... but now it may be too much.
what fish do you have, noticed any picking?
I really think a couple pics of your situation could help.