Affinity has no red cards at all, so Hydroblast has no legal targets in this matchup and stays in the sideboard. This matchup hinges on surviving the early artifact rush and grinding with card draw, not racing damage, so leave the main deck as it is. Keep your full Fog package to blank their alpha strikes from Myr Enforcer and fliers like Utrom Monitor and Refurbished Familiar, and lean on Preordain, Behold the Multiverse, and Plunder the Trollshaws to find more Fogs and land drops. No sideboard cards are useful against this opponent, so make no changes.