I couldn't find anywhere that showed how to wire two heaters into an STC1000, so I thought I'd share how I did mine.
Along with a drill, these are the tools I used:
I used the stc1000, a plastic box, two sockets, one plug, a connector block and some spare wire.
I cut a hole in the box, slid the stc1000 in, and used the orange clips to hold it in place
I drilled 3 holes for the wires that go to the plug and sockets, and a smaller one for the probe
I used this wiring diagram, ignoring the cooler bit, as I don't have one, and I decided to use two separate sockets for two heaters, so I could potentially spread then further apart in the sump...not sure I needed to do this. Could have been one double socket instead.
Step one of the wiring
The whole thing
I added some cable ties to stop the wires being pulled out by accident, then put the lid on.
I used this vid to show me how to program it:How to program a STC-1000 temperature controller - YouTube