What about are you using for water, RO
, do you need a new filter membrane, old membrane can cause problems. Which salt are you using? Maybe someone will have a good answer.
Do you think that maybe you could use a new layer of fresh sand. I am no expert here with SW
. Could it be Nitrates in the sand removed with the pwc
, then return the next day, just enough to bring the corals down? Then be processed by the LR
. Just thinking out loud. You suck up a small portion of sand at a time and then replace until it would be more or less new.
What equipment / setup are you using on the tank?