Spa and Hot Tub System Upgrades. Upgrade Index Next Installation Example These pages will give you an idea of what you can do with an older spa. The following spa retro-fits were done using the Gecko Pro-Pack. Spa Pack is skid mounted underneath a spa. Measuring the hole for the new side control panel Making extra room for it. Mounting is a snap! Drilling a hole for the thermal sensor A little silicone and putting the thermowell in place. The finished thermowell mount from the back. Note that mounting and installing the plumbing is the only thing left to do after these two items have been taken care of.  Next Example Here's a picture of an installation of a Gecko Pro-Pack on the ever popular  Leisure Bay Spa.