I know this is an old topic... I just picked up a used softub 300 .. I had to replace the motor, it was shot from water damage and corrosion. I was able to get it up and running.. But it seems I have some flaky electronic issues.. I was thinking about going the Arduino path.. I built a MendelMax 1.5 with a Ramps shield and arduino, so I'm a little fimilar ..
William,
Do you happen to have any photos ? or code you could share from this project ? I really dont want to spend 400 bucks on new softub controls ... 