I received a mini spa from a friend. Last week I filled it up and ran it for two days to make sure everything worked. It DID, heated up, bubbles and so on. I emptied it out and cleaned it, filled it back up and applied the chemicals needed. This morning I work up to the E1 code. I changed the filter and now the think is making a clicking from the GFI plug and the display. I unplugged it just to be safe. I’m wondering if there’s air in the system due to the chemicals cleaning out the gunk or if it’s a bad GFI?? And advice?