Kent Reef Salt vs Instant Ocean Reef issues?


New member
I have a 125 mixed reef w/ 30 gal sump.
Lots of Mushrooms, Tybee, Branching Hammers, Brain, Fox. all are thriving except the Branching Hammers are suffering badly.
My fish population is now reduced to 3. I am wondering if this is a now a lack of fish poop? OR possible switch in salt mix

This is an 7 year established tank, not much has changed.
Had to switch from Kent Reef Crystals to Instant Ocean Reef about 18 months ago? Turned off Skimmer and GFO to keep Phosphates up
I occasionally direct feed Cyclops & Plankton w/ BRS Reef Chili
Everything else in the tank seems to be thriving??
This has been going on for a month or so... the hammers are slowly dying...

CA: 460
KH: 187
Ph : .06
Mg : 1020 (Just started to add Mg)

I have pics here: