... Also repeating the exact same pool url is pointless. If you want same pool failover, try the same pool different nodes. For slushpool you could use something like:
stratum+tcp://us-east.stratum.slushpool.com:3333
stratum+tcp://ca.stratum.slushpool.com:3333
stratum+tcp://stratum.slushpool.com:3333
This is just in case a node fails or something. If you only fill 1, that 1 is going to be endlessly retried anyway you don't have to repeat it twice or thrice.
Yep, and I actually use two nodes of the main pool for Pool 1 and Pool 2 addresses, and the third one I use is a different mining pool for Pool 3 address.