Goniopora's always die its their job , Not many can keep them alive longer then a few months to a yr max. I really don't think your tank is ready right now its seems to be rather new . I'd give it a few more months to complete the cycle and let it ride. Thats that time to learn the needs of acros and get the water corrected for ca Mag and Carbonates . And get that PO4 and NO3 under control But until the Ammonia and NO2's are gone naturally then its not ready and they should be at zero for a month or two then add a acro.