[Cycle crash! Tetra safestart or prime]

5 minutes ago, Coronal Mass Ejection Carl said:

Stability contains heterotrophic bacteria instead of true nitrifying bacteria so it's no surprise that I often hear of it not working or even prolonging the cycle.

That makes sense.  Not sure why using that type of bacteria is marketed the way that it is.  I don't see how can help a new fish tank.

[Cycle crash! Tetra safestart or prime]

In my experience, Seachem Stability has had no noticeable effect on shortening the time it take to get a cycle going.  I have tried it many times over the years (even at very high doses).

Fritz's product is another matter.  I've only used it once recently, so I am not going to say for sure that it works.  However, my initial experience with it was very encouraging and I will be trying it again in the future.