I have some nuisance algae and I want to do a 3 day lights out. My question is do I just turn lights off. Or do I need to make tank dark with no ambient light also.
if you can adjust spectrum, you can just get rid of whites and reds and leave blue at a low level, and block from indirect sun...
and figure out why its there for when you turn the lights back on
You can turn off the whole light or set a low blue light rates like 25% for your tank about 6 hours one day.
But for reef, proper algae benefits coral growth. Although we can't get rid of all the algae, we can find out the reason of it and keep a low algae grow.