Boros Moxite is a red-white aggro-artifact deck with creatures like Kor Skyfisher and Glint Hawk plus burn like Lightning Bolt and Galvanic Blast. Much of their deck is red: Lightning Bolt, Galvanic Blast, Pursue the Past, Melded Moxite, Ragged Short Spear and Makeshift Munitions. That gives Hydroblast plenty of legal targets, either countering the burn or destroying a red permanent such as Ragged Short Spear. Bring in the Hydroblasts as cheap interaction. Blue Elemental Blast does the same job, but Hydroblast is enough, so it stays in the sideboard. Their white creatures, like Kor Skyfisher and Glint Hawk, are not red, so Hydroblast cannot touch them and the Fog suite still has to handle those attackers. Desert can snipe small attackers like Sneaky Snacker during combat, providing a bit of extra defense alongside your Fog suite. Bojuka Bog is marginal value against their graveyard-based Pursue the Past flashback and Sneaky Snacker recursion. To make room for Hydroblast, trim some of the slower card-draw spells and tweak the manabase; the core Fog and card-draw plan is otherwise unchanged.