I don't any of the qualifications in the title...
If you use GFO to drive the PO4 to near zero the GHA will start dying pretty quickly. But it will really piss off any SPS you have, probably kill several pieces. Your numbers aren't crazy high though. This is another reason why I have waited so long to add coral to my system. To get through the uglies.
I'd stop the Vibrant if you have any cheato but I think you said you didn't. If you don't then up the dose but don't use a doser add each dose all at one time. Hit it with twice a week doses at the recommended rate for you water volume. When you start seeing the GHA floating around in the display it's time to get your hands wet and start pulling it out. Once things are cleared up stop dosing the Vibrant, do a decent sized water change and have the CUC in place to keep it clean.
In the meantime if there is any GHA rubbing against coral frags remove it to stop the irritation and give them a shot at growing. You are also going to need to figure out a little better export system. Until the display is chock full of growing coral you need to help it stay stabile and a roller mat and skimmer aren't going to cut it alone. Carbon dosing will give you some help without needing to add anything beyond a doser, a trip to the liquor store and time reading up on carbon dosing. The skimmer will be the main export for the bacteria. An ATS instead of a fuge will actually cost to same or less and get you started faster. Just need to see if you have the room to fit one.
Beyond that it's a fuge or GFO reactor. GFO is not a long term solution for me, but it works. More frequent water changes will help, water out is an export too, just not very efficient.
**Edit** Dr Tims Waste Away and or Eco-balance are good products as well. I just wouldn't use either along side Vibrant. Pick one and stick with it.