Hello, I just picked up a used Hot Springs spa that is 110v 20amp. It has had the original GFCI plug cut off and replaced with a standard plug. I am setting the spa up in my garage and plan to share the receptical for my washing machine that is on a 20amp breaker. (Won't be running them at the same time). I am wondering if I can use a GCFI adapter in between the cord and outlet. The spa has 2 breakers on the control box already. Just want to be safe. Thanks for any help.