Songle Relay

[clemmi]

I got various Songle SLA-12VDC-SL-C relays and I want to make a sensor for a pond to turn off the pump if the level get too low (due top a major leak in the pipes for example).
I have two sensors that will trigger when the water is low and the pump is 220 V.
I don't want to use 220 V on the pond cables so I got the relays that work with 12 V.
I have the diagram connections for the relay and the pump and I now the basic connections.
My questions are:
Do I need more components (capacitors, resistors) to build the 12 V DC part or I just feed the 12 V from a small transformer?
Need/Should I have a relay for each line of the 220 V. ( the relay is rated 20 Amps.)? I have several relays so that is not a problem.
Do I need any capacitors, etc. in the output part for transients, etc.?
Thanks!

 

[dr pepper]

It will work of just one relay, you can switch both supply lines for completeness, a wall wart will power the relays so long as its output is higher than what the relay coil needs.
You can if you want put an x rated 100nf cap with a 100r 1w resistor in series across the relay contacts to quench any arcs, but it isnt totally necessary.