Hi, I recently bought a used D1 Spa Californian from 2014 and working on restoring it.
My Lay Z Spa was relatively smart, I had automations to start heating etc when I have PV excess.
Is there a best practice to make a legacy spa smart?
I used a shelly 3em Pro to monitor the 3 Phases. I am no able to see what the spoa is doing.
It would be perfect to control the pumps, filter cycles, temperature etc.
How would you do it?
Option 1.
replace the whole controller with Balboa/Gecko Parts that are “smart”
Option 2.
Disconnect the control Panel / Control Board and use high current switches (shelly) to control all the Pumps/Heaters (5kW) directly and monitor Flowswitch Temperature directly and program a software solution.
Option 3.
Combine option 2 with the existing Panel. but is this possible?
Option 4. hack the connection between Panel and Control Board
What do you think.
Option 4 would be the dream but imho pretty impossible.
I could live with 3 because I always used HA for controlling the lay z spa, I could isntall a HA Panel at hte Spa. However finding switches that could safely switch 5kW would be a problem. I recently killed a shelly by using it with my dryer 
Option 1 is superexpensive…
nils