freshwater nitrate problem

Question
we have a 75 gallon freshwater aquarium. for the last two weeks i have been struggling to get my nitrate down. a lot of our fish have gotten sick and died. i have tried treating their illness' while trying to get my nitrate down. i have given them a treatment of furum 2 and a treatment of melafix. i have tried adding more aquarium salt to our tank and the first thing i tried was a water change, i changed about 50% of the water. i have also put in nitraban, supposably to directly target the nitrate. we even bought another filter. all this and no success. do you have any suggestions? i am sick about loosing all these fish.

Answer
Hello,It may take a few water changes to get rid of the nitrates. I know that must be a pain having 75 gallons but 20-50 percent of the water change maybe once a week should help a lot. Try changing out your filter media, and get something maybe 'cycle' if any stores have it there, or any sort of beneficial bacteria should help you out a lot.