Thank you for the welcome! And yes, I am new, I started playing White this summer actually.
Hehe I was a bit surprised when I first used Surf in a double battle, I didn't know it hit all the opponents. Actually, I do use Seismitoad in double battles, paired with Yanmega, and use Earthquake, which Yanmega is immune to. That's mainly the reason why I chose Hydro Pump over Surf, even though it may miss sometimes, when it does hit, it's powerful enough to KO the opponent.