Zoa advice

Dear All: I am hoping to get some direction from the group. I have a 180g mixed reef tank with live rock, live sand (Aragonite), (softies, shrooms, Ricordea, Frogspawn, Hammer Coral, a huge clam, RBTA's, a ton of polyps and fish (mostly tangs). The tank is lit by 3 Ecotech Radion Pro's and 2 Vortech MP40's. I have a Reef Octopus Protein Skimmer, a Ca Reactor, and a 45 gallon sump with live rock in it (I recently removed bioballs and replaced with LR). I dose carbon, MicroBacter7, AcroPower, NOPOX, and NeoNitro. My levels are pretty consistent: Salinity: 1.026;Temp: 78.3; pH: 8.66; Ca: 430; Mg: 1280; NO3: 8.73; PO4: .64. My ongoing problem that I need help with is that I am dying to have a tank full of Zoas, but they keep dying off. I can't seem to keep them alive for more than a few weeks, and they NEVER grow (everything else grows like weeds). I have changed my lighting schedules various times, as we'll as my Vortech's, tweaked my dosing here and there, and now I am waiting for a GFO Reactor from BRS to get my Phosphates down. I know my Nitrates are elevated, but I understand that this should not have much of an effect on the Zoas. Any suggestions?