You might also want to keep eyes on the water PH as well. When there is too much nitrate produced, eventually the PH will crash. Too low PH will affect the bacteria growth and stall the fishless cycling. You can prevent this from happening by doing a 50~70% water change when you see the PH is dropping fast. Make sure you use the water conditioner on the new water before you put it into the fish tank. Chlorine in the tap water can kill the bacteria.
By the way, what is your water temperature? Are you using an air pump?
Raise water temperature to middle 80s and increase oxygen supply to the water can both shorten the time required for fishless cycling to complete.
