Ok, that makes more sense whay you'd think it was TSS that did it for you, but I have read all over the web people saying they were able to complete a full cycle in less than 3 weeks with no seed material, so the time frame still does not seem "magical" and definitive proof to me. I have no idea if these people don't know what they are talking about or if they are telling the truth how common such a timeline is, nor do I know how predictive the length of the ammonia part of the cycle is for the nitrite part. I know they lasted about the same amount of time for me(a little over a week), even though my ammonia never read above 0.75 ppm and my nitrite jumped to 2+ ppm.
As far as seeding goes I'd say that it is one or the other. Add safe start or seed. Safe start is supposed to start your beneficial bacteria culture so why add it if you have a culture there already by seeding? Know what I mean? At that point I can understand why there probably wasn't much difference because it seems like they both just did the same thing.
Why does it have to be one or the other? It not only matters WHAT bacteria you have but HOW MANY. Remember that these are common bacteria with spores floating in the air around us all the time. With this logic, why ever seed at all? You can get a perfectly acceptable beneficial bacteria colony from the air. The reason people do is that bacteria divide exponentially. You need enough to eat through however much of these chemicals you are producing every day. Exponential reproduction means that basically, the bacteria divide in 2 given a set amount of time. So, 1 bacteria divides into 2, those 2 divide into 4 in the approximate same amount of time it took the first one to divide, then those 4 divide into 8 and so forth. Say it takes 5 minutes for a bacteria to divide (making that up). At this rate, it would take you an hour to get 4000 bacteria from 1 "starter" bacteria. However, if you START with 4000 bacteria, you get 4000 more bacteria in just 5 minutes! Play with the math and you'll see that this effect just gets more pronounced the more bacteria you have, meaning it takes less time to get to the final number of bacteria you need for your bioload. So that is how seeding "jumpstarts" the bio filter growth.
Then, there is the fact you need 2 types of bacteria - one that eats ammonia and one that eats nitrite. As you know, hwne cycling you have to keep giving the bacteria food or the cycle will die. This is because the bacterial colonies will only be as big as the food will support, and if there is not enough food, they start dieing off. So I (and most people who seed) put a lot of beneficial ammonia eating AND nitrite eating bacteria into my tank with the seed material. My NEW tank that had ammonia within hours but did not have nitrite showing up as testable in the water for another week! So it seemed reasonable to ME to suspect that at leats some of the nitrite eating bacteria I had introduced in the seed material had at that point died off. That was the point at which I used TSS because I figured, hey, what could it hurt?
And who knows? Maybe it worked! Maybe that's why my nitrite cycle went as fast as the ammonia.Or maybe not. I personally figured it was worth the money to at least try! My point is you could never know whether it actually worked based on use in any given tank. The only way to know is to trust the company's own research data (at which point it also makes sense to trust what they tell you about dechlor and TSS) OR to set up an experiment yourself with multiple tanks, half of which randomly get TSS and the other half that don't, and control ALL other variables between tanks to the greatest extent feasible.
Like I said, the possibility it is helping is worth the money to me, and their data seems pretty good.