Ricky it seems as if the rocks are leaching "fuel" for nuisance algae. Im guessing there was die off deep within the rock. You may not even detect anything because the algae is taking it up as it's being released. My reef took about 7 moths to fully come around. You may have to wait it out. It'll will soon come around. Just my opinion.
That is my thought, the rocks are very porous and they have been with me for 5 years so they had plenty of sponge growth and other organisms living within the rocks prior to be drying them out. I believe once the "die off" is complete the algae will be gone. The overflow is completely covered in purple coralline algae but the live rock has none due to the hair algae covering ever possible inch that the corals are not occupying. I just hate looking at it every day and it could take another 2 to 5 months before it all dies off.





