Why the hell do my sps keep dying

[dabandit]

I dose trace elements,cal,phyto and zeo

[dabandit]

test kit is professional grade test tube style

[dabandit]

I've never had to dose for ka my water changes keep that in check 10% every3 weeks with instant ocean

[dabandit]

and no softies anymore

[dabandit]

all sps were given 12'' away from any other coral

[dabandit]

Im stumped I've tried on and off to keep sps for about 2 years allways the same result but only in this system,could it be parasite or bacteria? and what can I do?
P.s no cyano i system but some hair algae on back wall for tang

[fencer]

Check your REDOX potential

[o.c.d.]

when you are adding the corals are you starting low in the tank? how about the age of the bulbs?

[mark]

With a Ca of 450, chances Mg is okay (from a observation with low Mg, I'm unable to get my Ca up).

Source water?

[dabandit]

Ok where do I start;I dont dose ka,flow also comes from sump return at some astronomical rate,they are dying bottom up,i use 2 decent hydrometers and reference both for acuracy,I cant find a mag test kit at any lfs ive checked so far but i assume its okay because my calc and ka are high?,system is approx 2 years old,i dont keep softies anymore,i have'nt seen any bugs or what not even at night and yes I aclimate properlly but i dont use any products in doing so,no I cant even keep monti ALL sps species have died

So heres what I've got from you guys so far;slowlly raise salinity,bigger koralia......?