I took a while in responding to this properly because I was trying to find a blog I came cross a few years back. It was a hobbyist from the US who on entry to this blog got a lab to take a microscopic look into what is actually in these bottles.
May I ask you which products did this guy test and how many years ago? You are basing your opinion on one blog written years ago by unknown writer? I am basing mine on personal experience with a product.
My argument is that Tetra Safe start worked for me, but I do agree that other similar products may not have been successfull in the past. As far as I was able to research, Tetra Safe Start has not been on the market for very long time at all and also the company that created the refrigerated version of it-BioSpira only opened in 1990, which means anything based on previous research could not have worked as it contained the wrong nitrite bacteria:
There is much debate within science (not to mention the hobby) as to exactly which species of autotrophic bacteria perform the vital functions of the “Nitrogen Cycle” in our tanks. Historically, it was thought the species associated with the conversion of ammonia into nitrite was Nitrosomonas europaea and that the species associated with the conversion of nitrite into nitrate were Nitrobacter, Nitrospina, and/or Nitrococcus. This “belief” was based upon the correct fact that these are the bacteria primarily responsible for maintaining the nitrogen cycle in soil. To this day, most bacterial additives (quick cycle products) available to aquarium hobbyist contain these bacteria. Unfortunately, it has been discovered that this is not the correct combination of bacteria that exists in our tanks. It’s no wonder that aquarist worldwide have come to the combined conclusion that these “quick cycle” products do not work. They (as in, the industry) are packaging bacteria that function in soil and selling it to us as something
Research conducted by Timothy A. Hovanec (formerly of Marineland Labs, now the founder of Dr. Tim’s Aquatics) has identified the correct combination of autotrophic bacteria performing the nitrogen cycle in our tanks are Nitrosomonas marina (converts ammonia to nitrite) and Nitrospira (converts nitrite to nitrate). I am aware of only two “bacterial additive” products that contain these bacteria, Dr. Tim’s Aquatics “One and Only” and Tetra SafeStart. United Pet Group has purchased Marineland. In the process, Dr. Tim bought out Marineland Labs (the creator of BioSpira, which is no longer available), forming “Dr. Tim’s Aquatics”. United Pet Group also owns Tetra. Tetra has subsequently released Tetra Safe-Start, which appears to be BioSpira repackaged in a form that does not require constant refrigeration (just as One and Only does not require refrigeration). It may be that availability of actual functioning product, containing the correct combination of living bacteria, may remain limited to these two products due to patent restrictions. Dr. Tim and the former Marineland Labs (now Dr. Tim’s Aquatics) hold the patent and United Pet Group/Tetra received co-ownership via their purchase of Marineland.