Hi. I posted this question in the wrong spot before.Rookie error. sorry.
I have a used tub with limited info. I am looking for imput on setting this tub up electrically and any other comments about it. The spa pac is a Series SPH 2(the 2 is in roman numerals) by sta-rite. It is 240 v ,1.5hp pump, 6 kw heater, 35.7 max amps, 99 usgpm with a 40 amp dual pole breaker as the main shut off. I will be getting an electrician to check my set up before powering it up. What size GFI would be required for this. My guess would be a 40amp with 8guage wiring. The total run from the panel is aprox 25 ft. The tub is outdoors. Thank you in advance for any help offered.

That main breaker shut off was 50 amp not 40.

Most typically spa GFI breakers are sized at 50A and since your spa is sized with the same size breaker, you will be ok with a 50A. As long as your spa is protected independantly (it's own breakers) you can run virtually any size same or larger GFI breaker as the feed. The only thing you have to be sure to do is size the wires from the GFI to be able to support the maximum current the GFI can handle

Thanks for the info charger 1 . I have been reading your posts and they have provides me with a lot of info. You have refurbished 11 tubs but I think you've had a hand in refurbishing at least 100 more!