This is the set I have on my sandstorm Gastrodon.
EVs: 252 HP/76 Defense/180 Sp.Attack/
IVs: Make sure (for this set) he has 30 Sp.Attack IVs for HP electric
Scald: Good Power, STAB, good chance for burn
Earth Power: Nice power, stab, chance for lowering target's Sp. Def
This guy is good on a sandstorm, being that water types don't affect him.
HP Electric: OK power, and with...
Ice Beam: You now have the bolt/beam Combo