with wiring, just contact the local inspector! Sorry I had to laugh at the concept someone would actually know what was 'approved'. Locking up the Apex is not a bad idea. It would help keep the kids out too. If you give the kids access to the Apex programming, make sure you back up the working scripts before they change them. The logic can get a bit obscure and you'd want to restore it all at the end of the day. Big Lots and Diablo - it's a sign from above to visit both! To do two temps you'd need another module. IIRC both the PM1 and PM2 have temp ports. I don't use the ORP sensor on mine. I use it as a second pH port (I don't trust in pH probes!) .