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.
Side Control installed in the flat space area above the original air push buttons.  The air buttons are now non-functional.
Overall View of side control mount. Close up.
Overall System installed under spa.  Red arrows indicate water flow, blue indicates air flow. Thermowell installation from the back.
Basic Diagram of the system as installed.  This is not a pretty installation (most aren't), but it is entirely functional, and works well.  One thing to note, insulating foam (the wall type available at Home Depot or other suppliers) board has been constructed over the pump and blower to reduce the amount of noise radiated from this installation.  Venting for the pump and blower is accomplished through the bottom gap of approximately 1.5 inches between the foam and the skid, and holes cut in the top of the "box", (top not shown).

The advantage of the service valves allows for the removal of the entire skid in minutes for service if necessary, as well as pump repair and heater element replacement without having to drain the spa.
This shows the right side view.  Note the blower check valve and the "T" discharge to the spa jets.  The filter on this particular spa is a suction side filter, with the filter elements installed in the skimmer.  On your spa, if you have a pressure filter, you will need to route the discharge from the heater to the filter before it gets to the spa.   Next Installation Example