Does high KH eliminate Cyanobacteria?

[mandarin man]

Thanks for your help

My tank is approximately 6 months old. I did upset the balance like a month ago by changing light bulbs, remove the ceramic biological fitler, and threw in 30% of uncured live rocks (my stupidity). It could have been the die off the new rock that causing this, my mistake. Now I am fighting hard to balance the system again.


Would the corals and the fishes be OK with three days without light and food?