It is difficult to say as I am not familiar with your filter...That being said if it is just a mechanical filtration then it is possible that there is not enough bacteria, but the bio filter is not the only place the bacteria grow. They grow on any and everything in your tank. Your wool filter...
I don't know about other brands but the one I use PRIME works extrememly well. And the bonus is that it will not interfere with the cycling process. Primes turn ammonia into ammonium which is still food for the bacteria. It also reduces nitrites, nitrates and works as a dechlorinator as...