Perched Urchin
New member
Removing/replacing rock.
If it were PO4 from filth build up, then a good cooking, like what you would do with dead rock that had been previously live rock might work.
But it would still mean removing all the rock and basically starting over.
I am no expert. Obviously not suggesting that on my advice alone you rip apart your tank - just a possibility to think about. It sounds like the "usual suspects" have already been ruled out.
If it were PO4 from filth build up, then a good cooking, like what you would do with dead rock that had been previously live rock might work.
But it would still mean removing all the rock and basically starting over.
I am no expert. Obviously not suggesting that on my advice alone you rip apart your tank - just a possibility to think about. It sounds like the "usual suspects" have already been ruled out.