I just started getting over the same problem recently. An algae problem led
me to reduce feeding to 1 time per week. Whites were shut off. Nitrates and phosphate were at 0 but I still had a huge algae problem. I even put half my rocks in a curing bucket with no lights. After months there was still algae.
I believe the reduced feeding and lights led
to my coral health issues.
All the other things only help prevent NEW algae from growing but won't get rid of algae you already have.
Only 1 thing worked to kill the algae. A hearty clean up crew of mostly hermits. They have been destroying the algae and just today I put all the rocks back in the DT. I have 80 crabs now in my 110 gal
tank. Draft blue leg, electric orange and scarlet hermits are great at algae control.
Check my thread in this group called "Grrrr green hair algae " or something like that.
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