Adding products that cycle a tank dont actually cycle a tank. They might claim to, but in reality they might speed up the process from months to weeks. It might seed your filter with some of the beneficial bacteria responsible for your cycle, but not enough will establish to be considered "cycled". You still need to manage waste in the tank with water changes until your cycle establishes. Depending on stock levels, volume of water etc, this could require daily water changes for a while.
As said you should target 0.5ppm combined ammonia + nitrite as an upper limit. You have 1.5ppm nitrite, so to get that to safe levels will require 2 x 50% water changes.
Changing filter media isnt a good idea as you will be throwing away the bacteria responsible for you cycle and need to start over to some degree. Unless its falling to bits, just rinse and reuse. Chlorinated water can also kill off bacteria, so use dechlorinated water or water from your tank. I presume your filter is the type with 2 cartridges? If you have to change them, dont change them both at the same time. A better option is to throw away those cartridges, cut some sponge and get some biomedia and use that in your filter.