I am doing hypo in my 180 gallon tank with a 55 gallon fuge. I took all my LR and inverts out and currently have the salt level at 1.013-1.014 and will be dropping again tonight and tomorrow morning. Fish and a 2 inch sand bed remain in the tank. The nitrates in the tank are really high and I know its from taking out the LR but I need a solution to fix this. I have changed about 90 gallons of water in the past 2 days. Should I buy a canister filter or put carbon in the tank, need advice.