refugium or macro in the display (for FOWLR) to export nutrients is usually my first choice.
you can do water changes frequently, as long as you let the water circulate at least overnight, and match sg, temperature and pH pretty well.
I wouldn't change more than 20 percent at a time if it's not an emergency, but you can do this daily until you get the nitrates down. in tanks where nitrate control is a problem you can try the following:
feed lightly
reduce stocking levels
get a better skimmer (gets the stuff out of the water BEFORE it becomes nitrate)
set up a refugium with macro
set up a remote DSB (I haven't had great luck with DSBs, so I recommend one that is easy to remove/disconnect if there are problems)
increase frequency of water changes and stick to the schedule - e.g., if you normally do 10% a month, try 5% a week or 10% every two weeks
I have never tried a denitrator, so I can't recommend it.
