220 gallons is really too big to dose with Flourish nitrogen or any of the other Flourish macro fertilizers. Flourish Excel should be dosed daily at 1 ml per 10 gallons, so you would need 22 ml per day. At major water changes you dose 5 times that much, or 110 ml. So even a 500 ml bottle would go very fast.
You will do much better using pressurized CO2 and dry fertilizers - KNO3, KH2PO4 and CSM+B. At least the cost will be much, much less.