Sps dying

[reefking807]

So my sps has been randomly dying off. I don't know why.
My alk is 10.5
Cal 400
Phosphate.75ppm Red Sea test
Nitrate maybe be 5 ppm
Lighting tec light 8x54 bulbs were bought in Aprilish timeframe. 10hr light schedule. I do biweekly water changes of 20 gallons Reef crystals

They were doing really good out of nowhere they started drying. The polyps aren't extended. The skin is on there and no rtn stn. Help

 

[twilliard]

A picture sure would help!!

 

[ammari33]

Because of high PO4 concentration, it should be within 0.04 ppm

 

[Salty1962]

Alk and Ca are out of whack..

 

[DLuce510]

PO4 wouldn't wipe out sps like that, I 've seen way higher, are you using a dosing pump or dosing by hand, maybe temp swings. Are your corals Mariculture could be a lot of things but its usually from parameters being all over the place.