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The tub is a Hot Springs Highline, owner said around 8 years old so I'm guessing it's a 1998 or thereabouts. Not a lot of fancy jets, but I just wanted a starter tub anyway. (Hot swirly water is good enough for me!)
If it's not too late, ask the previous owner if you can just take the breakers. The box itself can stay, and any other breakers which might be running other things can sure stay.
If any dealers would be willing to give me an idea on pricing for the GFCI boxes (with a 30A and a 20A breaker), I'd appreciate it, I realize they're normally bundled with the tubs, but I'm getting some wildly different quotes to buy it separately.