My system is over 2 years old now and I have a lot of fish waste in the gravel beds.
1. how long can I go without new fish in the fish tank?
Place a 4" perforated feeding tube for the worms into the bed. Place table scrapes in the tube to feed the worms. Cover the tube so that the worms will enter and feed. You may not even need fish if your nitrate levels remain suitable.