Dying Branching Hammer... Help..??

[yachtdr22]

Greetings,
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?

1.025
CA: 460
KH: 187
Ph : .06

I will be posting pics soon...

Thanks for the help!!

 

[yachtdr22]

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??
I will post some pics once the tank wakes up...
This has been going on for a month or so... the hammers are slowly dying...

 

[yachtdr22]

pics

pics

some pics show the rest of the healthy tank.
is this a water quality issue or nutrition?

 

[yachtdr22]

more pics

more pics

More pics...

 

[jerrym21]

Would you happen to know what your magnesium level is?

 

[yachtdr22]

Would you happen to know what your magnesium level is?

It does look a little low.
1040
I will start to dose a little.

I have been using Kent Salt and never had to dose Mg before.. Thanks!!

 

[jerrym21]

I would try to get it up to 1250-1300. I've found that my Hammers and Torches do very well in that range. Some people go even higher into the 1400+ range.