Am I missing anything? 2.5 year reef going downhill

[FL_Reef]

Last week my orange setosa colony died and now overnight a small acro colony died. The setosa had been in the reef for probably a year and a half doing great. A few days back it started stn and I couldn’t save it. I just now noticed one of my acros that has been in the tank for over a year bleached overnight. It looked fine last night. My scoly is shriveled, my torch looks bad but most everything else looks good for now
Not sure what all to do. I’m mixing up some saltwater to do a water change. Problem is my salt mixes a couple points higher in alk than I keep my tank at so the water change can’t be too big. I put some new carbon in a filter sock and I guess I need to do an ICP test.
There has been no major changes recently. Parameters are pretty stable. I’m thinking it could be bacterial as I put a dying hammer that was in my frag tank from reef a palooza to see if my more established tank would help it. It didn’t. Now I have another hammer same situation in there.
Parameters - nothing out of the ordinary for my tank
Salinity 1.024
Temp 77.5-79
Alk 8.6
Cal 440
Mag 1380
Nitrate 12.4
Phosphate 0.2
Any ideas? I don’t know what to do if it is bacterial or if it spreads like that

 

[CoralB]

Maybe hook up a UV light and bring you phosphates down to 0.05 ish , look for bad stuff on the corals that are failing in health . Dip if necessary . Did you dip the coral from reefapalooza ??? Phosphates are high though

 

[FL_Reef]

Maybe hook up a UV light and bring you phosphates down to 0.05 ish , look for bad stuff on the corals that are failing in health . Dip if necessary . Did you dip the coral from reefapalooza ??? Phosphates are high though

I have a uv light running. Never tested the exact flow so not sure if it’s working correctly. Phosphate is high but pretty normal for my tank. It is usually in the 0.15 -0.25 range. Been that way for a year or more with no issues
I didn’t dip the coral. I’ll try to look closely to see if I see anything. The thing is my acro looked perfectly normal last night
Thanks for the reply
If it is bacterial and I get my uv dialed in, would that be the cure?

 

[CoralB]

It would help especially the bacteria in the water column . But I would try to identify what’s going on with the frags that are not doing well . Possibly dip if necessary. I can’t tell u what to do but you should always dip and quarantine if you can any new coral no matter where or who you get them from . Not just for bugs and disease but bubble algae , flat worms , aptasia, and any other critters or critters eggs . At the minimum you have to dip .

 

[Spare time]

Can you list the test kits? Do you have an accurate way ti measure pH? Do you calibrate whatever you use to measure salinity? How do you measure temperature? Do you have a temperature alarm? Also, please list the inhabitants

 

[FL_Reef]

Salifert for alk cal and mag
Hannah for nitrate and phosphate
Last time I checked my refractometer with the liquid it was spot on but that’s been several months. Will check again
My temp is a brs titanium heater with the ink bird controller
Haven’t checked ph in a while. I have an api test kit. I’ll check that
Tank inhabitants. Nothing has been added in at least 6 months probably more
Bristletooth tang
fox face
2 clowns
Azure damsel
Hawkfish
Filefish
Mandarin
Fire shrimp
2 pep shrimp
Conch
Misc snails and crabs