I have a question regarding wiring for my Hot Springs Spa. The spa comes with a subpanel for two GFCI breakers, one 20-amp and one 30-amp. I have 220 wired to an existing subpanel located right next to my spa location. The only difference between my sub panel and the wiring diagram on the spa controller cabinet is that in my existing subpanel, the neutral (white) and the ground (bare copper) coming from my main panel are connected to the same bar. The wiring diagram from my spa shows these two wires as connected separately. I checked my main breaker panel and all of the neutrals and grounds are connected to the ground there also. What is the relation between these two, and can I connect them safely in my sub panel? Since the spa is wired for connection to two 2-pole breakers, the wires that go out to the spa include four black wires, a white and a green. I am comfortable with all of the connections except the neutral/ground connection. I attached a picture of my subpanel showing the existing wires without any of the spa wiring. The two single-pole breakers are not related to this issue. Thank you for any advice you have.

The sub-panel in the picture is wired wrong. Ground and neutral need to be separated in any sub-panel. Look for a part number for a "Ground bar kit".

In the MAIN panel ground and neutral are connected together. This is where the Electrical reference of zero volts occurs.