Hope after 10 years all of you are on this site and read my reply. I am experiencing the same thing. The vibration in my house from my neighbour’s spa has landed me in hospital twice! The cost for me has been enormous (audiologist/ENT/ cardio electrophysiologist etc) as I have existing health issues that the vibration exacerbates. I’d be happy to pay for a technician to fix it after this expert told me 100% the spa is behind this. He said it is what it’s sitting on, if the spa is on deck or hard surface, if the pump is wrapped in rubber or not etc. if it’s an old pump or attached to the spa and there’s no casing etc etc. Hope you worked it out. I now have to sell as it is detrimental to my health. Sad huh when it’s a relatively easy fix by the spa owner.