SPS doomed

[brc0488]

any1 know why the only sps i can house in my tank is a scroll coral my params are :

PH: 8.1-8.2
Nitrate: 40 (im guessing this is the problem, but why does the scroll coral survive?)
Nitrite: 0
KH: 250-300
salinity 1.023
have enough water movement return is a mag 7 with two PH 50's on either side of the tank (the tank is a 55)

light 250 MH with 55 watt Pc (actinic)
i tried a small piece of monti cap a while back and it died almost overnight and then yesterday i tried a small piece of digitata but same thing happned. Yet the scroll coral has all of its polyps extended and looks very healthy.
other corals in the tank include 3 types of acan, 3 types of mushrooms, candycane, xenia, star polyps, BTA, zoo's, im sure im missing one. also the tank is over a year old now. thanks for any advice

 

[old salty]

Salinity is a bit low. Nitrate isn't too good either. What are your calcium levels? Have you checked phosphates?

Finally, what type of acclimation are you performing?

 

[brc0488]

ill check calcium and phosphate tom is i can find the test for P04 acclimation i usually drip but with the digi i had to cut it short because i had to go out that night that i got it....that might have something to do with it...

 

[lesniewv]

What's the KH? If you're talking about CaCO3 in ppm, then it seems very high, If I remember correctly, each 50ppmof CaCO3 equals approximately 1 meq. Most people recommend around the 3 meq level. KH of 250 - 300 would be aournd 5+ meq.

 

[brc0488]

i have no idea what u just said...but sure

 

[brc0488]

i was talking about alkalinity