No there is more than enough there to get you close to that 4 ppm range which is better in the long run because you'll build up more bacteria in the long run. But like I said you don't have to be exact in this instance IMO. If you were buffering 2 part it would be a different story. But your just getting your cycle going and getting it somewhere in the 2 to 4 range is ok.. But with your size tank I suggest getting it to that neighborhood of 4 ppm number just so you have a nice sized active colony of bacteria.