Time to fully cycle varies depending on the size of the aquarium, the amount of "seeding" from an established tank, temperature, oxygenation, etc. Larger tanks and "virgin" cycles, i.e., those using little or no media from established tanks, will take longer to cycle, possibly 3 weeks to a month. I've been able to cycle smaller tanks, using established filter media, in as few as 3-4 days. The major advantages of fishless cycling are: 1) no exposure of fish to ammonia and nitrite and 2) allows you to fully stock your tank upon completion of cycle.
I just set up my new 300 gal. I put the gravel and filter from my 150 that was up and running along with the filter ( not cleaned) and about 50 gallons of water Will this speed up the process?