Any Help.

[Delphinus]

I've never heard of using Formalin in anything but a temporary dip. I beleive formalin is basically "formaldehyde" so I'm afraid this could have a very bad outcome. Run large amounts of carbon, continue to do water changes maybe.

It might even be better to remove the livestock to a new system. See if the store that sold you the formalin can help out with that, at least with the fish and anemone.

Good luck.