Fluval is not much better than Stability. Almost none of the starter products will contain Nitrospira. Use either Dr, Tim's One and Only or tetra's Safe Start. Both contain live Nitrospira.
Not only do these bacteria oxidize nitrite, but recent science discovered they are able to oxidize ammonia straight through to nitrate as well. This may well explain why studies have shown that there are a lot more Nitrospira than Nitrosomonas or Nitrosospira in cycled tanks. Without looking it up, I recall it is about 2% of the bacteria are the ammonia oxidizers and about 12%-15% are Nitrospira.
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https://pubmed.ncbi.nlm.nih.gov/?filter=simsearch2.ffrft&linkname=pubmed_pubmed&from_uid=26610025