Something Spawned

[Magickiwi]

So something spawned in my tank after a 20% water change and my tank now looks like there is a blizzard under way.

ORP went from 328 to 24 almost immediately and the fish went bananas.

I have a small maxima clam in my tank and it's the only thing close to big enough to make that big of a mess.

Just changed carbon and POx4 last night. Am I on the hook for another water change now?? Skimmer is wide open now and none of my corals seem poorly.