some people have said dosing Vodka or sugar works with nitrates, there are links on RC somewhere. But if something goes wrong bye bye tank.
Water changes are your safe bet, every few days do a bigger water change than you would normally do. If you do 5, go for like 7 or 8
If you have 30 gallons of actual water volume, then it would take 6 water changes to completely get all of the water out.
I dont remember skimming getting rid of nitrates and never have seen anything really good in a form of some sort of media in a bag to get rid of nitrates.
to my understanding it was clams, chaeto and water changes
but adding a clam in now , would probably not be good for it as the nitrates are so high.