I just wanted to add that my tank stalled for over a month (1ppm of Ammonia and Nitrite each, and 10ppm Nitrate) and the PH wasn't the problem (still over 8ppm). nothing worked, and while I know you have to be wary of cycling products, frankly, I got fed up and quite desperate. I wish Biospira was sold around here, but alas, the next best thing is the Stress Zyme. So, I figured, what the heck, why not try it? The worst that can happen is my tank still doesn't budge. So I added some, waited, and the next day the Ammonia was down to 0. I kept adding Ammonia back up to 4 (sometimes 6) and the levels were going back down to 0, though eventually it started slowing down again. So I added more Stress Syme, and it speeded back up again. Now I have fish swimming in there, and I'm happy (are you kidding me? I had that tank cycling from November 30 until only last week! That's ridiculous!). Granted, my bottle eventualy ran out (as it will) and I swear, the next bottle didn't work as effectively as the first (though it did work). I think it comes down to what you're willing to try and just how desperate you are. I agree that most, if not all (except Biospira) cycling products are just junk, but I think there really is something good about Stress Zyme. It's the poor-man's version of Biospira, lol