I just setup my newest tank on Sunday. i added 20 lbs of rock from someones established tank and about 5 lbsof the rock from my pico tank. Since there was a bottle of "bacteria" in the actual tank kit I used it.
I had an ammonia spike of .5 for one day. never saw any trites and the trates are at 5. Tjose amounts are from the live rocks die off. If this bacteria had worked the cycle woudl have been longer and I would have seen trites at least something.
I also have setup several other tanks using the exact same method but NOT using bottled "bacteria". Same result everytime. Ammonia spike, no trites then trates all within a few days. I've also cycled with pure ammonia on my first tank. used live rock from someones tank and dosed ammonia to 4ppm. No bacteria again. Ccycled this time with nitrites showing. Cycle was done in a week.
I didn;t believe the bacteria in a bottle thing before and now after just using it I definitely don't. How can any nacteria stay in a bottle and alive for months? Suspended animation? This is all my opinion, but I feel I have a strong case as I've used it and not used it.
My vote is to spend that money on asomething cool for your tank instead, liek a fish or a coral. Or on any number of things you know youre gonna need with a sw