Something is wrong with my tank-

[Jer97]

So I have a Mr. Aqua 12 gallon long reef tank. Made my own sump- also have about a 70-100 gallon skimmer on the tank.
2 kessils A150w - about maybe 13-17 pounds of live rock and about 10 pounds of live sand.
a couple fish in there that im going to transfer when to my 55 when they get bigger
All my fish are happy doing fine not one of them seems sick or unhappy.
But every coral I put in this tank just dies..
The parameters seem good too
0 Nitrates
.25 ppm phosphates
500 mg/L ( ppm) Calcium
KH conversion 9

Had the tank up for about 8 weeks now..

 

[Livi101]

Have you checked your iron and copper? was it a new tank when you got it? what flow do you have?

 

[silverado61]

I noticed your Calcium is a tad high. Most corals feed off Nitrates so a zero reading is not optimal. What about your Ammonia and Nitrite readings? What type of tests are you using?

Also, in my opinion, 8 weeks is too early for most corals. What species are you trying?