Bio spira rapidly gives you a biological filter, the Seachem matrix is surface area for the bacteria. If you want you can cycle the tank by feeding the bacteria some ammonia you can get from a hardware store. Make sure it’s pure ammonia no additives. Then do a stress test by seeing if the bacteria can process ammonia @ 1-2ppm in 18-24h.
Bio. Spira, says you can add fish right away, the ammonia produced by the fish will help feed the bacteria, keep an eye on your levels by using a Seachem ammonia alert and do a water change if ammonia is detected
There are other bacteria in a bottle, I prefer using bio-spira and recently added Seachem matrix and seeded it with another bottle of bio spira, I was having a hard time keeping ammonia down with a tang in qt. The sponges and ceramic rings that come with a hob filter weren’t cutting it. I added 3 additional sponges and still had issues keeping ammonia down for more than 2 days.
I added 1L of matrix which I think is good for 200 gallons. So far ammonia has stayed at zero for 4 days.