Still feeding flake?
Try frozen food defrosted and rinsed.
Lots of PO4
in flakes and frozen(it is the preservative) which is why you rinse the frozen.
I wonder if the po4
is leaching from rock(not so uncommon)?
Are you keeping up on fresh phosguard?
Checkout the chemi pure elite or GFO
for chemical solutions.
SeaClear is a liquid for spas that reefers are using to remove po4
The use of this is similar to carbon dosing as an example I believe.
Lanthanum Chloride AKA SeaClear for pools - Reef Central Online Community
Just putting thoughts out there.
Lights although new still only 8 hrs?
What are the new lights?