Thanks, unfortunately I bought the hot tub from one of the expos that everyone hates so much on here, that was before I discovered this forum by which point we had committed. That said all is well with the spa so far. Tonight I did fill it and added the metal gon, everything started up fine, the pumps all ran, the heater is heating it now at about 5 degrees an hour uncovered - we stood watching it for half an hour, cover on now .
I plan to test the water tomorrow evening, adjust and shock it, then jump in once the water is ready.
My biggest fear is lack of support when the day comes that it needs some maintenance, but not much I can do about that right now.
Cheers
Jonathan