By good science I mean several things:
1. The proper bacteria needed have been correctly identified and will be what is found in the brands that work. There are many published studies on this. One of the most important discoveries is that different bacteria will dominate a system based on the general ammonia levels. Another way to state this is ammonia levels select for the specific ammonia oxidizing bacteria which will work best in that situation. This doesnt mean other strains may not be present, only that they are relegated to a lesser role. That is why it is rare to find the ones that handle large ammonia doses in tanks longer term. They may be there if ammonia levels are high enough at the outset, but they wont last.
2. Science has shown over and over that the nitrifiers do not die quickly nor easily when they are subjected to periods of no food and low oxygen levels. They can basically shut down and go into sort of hibernation and wait for better conditions to revive. The healthier and stronger they are at the point they have to do this, the longer they can last. If you want I can provide you with links to multiple studies on this none of which are in any way connected to the companies that bottle and sell these products nor the scientists involved with the products. You can find this about more than just tank strains, it also applies to waste water treatment, drinking water treatment and aquaculture. I can link you to a good abstract which shows nitrifiers being kept dormant for 7 months and regaining full capacity within 11 days of being "revived". The heterotrophic bacteria did not fare as well and took 16 days to get back up to par.
3. Even when they have been kept in the bottle for a long time they can still be revived. it can take longer. So an old bottle past its prime can still do more good than no seeding of any kind at all. I can link you to studies which show nitrifiers surviving in dry soil for decades. There is a difference between having viable bacteria that can be revived over time and having fresh seed material from an established tank. The former will reactivate and recolonize a lot slower than the fresh bio-media. However, this is not the same as saying they are all completely dead and useless.
4. Many of the problems associated with the initial products, aside from being the wrong bacteria, were because the bacteria should be grown on a substrate of some sort which they now are. When you shake the bottle and pour them out you can see this- it almost looks like chalky clumps. This is not to be confused with substrate references which are directed at what they eat like ammonia etc. A better understanding of this can be obtained from reading about biofilms and extracellular polymeric substances (EPS) in relation to how the bacteria live.
5. Many of the folks who have problems getting the products to perform as advertised are at fault for failing to follow the directions rather than the product not being any good.
6. Public aquariums with tanks of 2 million or more gallons rely on these products for their exhibits. Does anybody believe a public aquarium is going the spend the money to cycle 2 million gallons of salt water using one of these products and then fill the tank soon after with live dolphins? While we argue over cycling issues in our small tanks, the people in charge of such aquariums are not risking their own job or the public relations disaster a tank full of dead dolphins would bring. While this isn't science it sure make a lot of sense.
There are a lot of research studies out there which will all support the above. I have read a ton of them and, trust me, they can make your head spin. I have posted references and quotes from a lot of them in many of my posts on this site. I could post a list of 20 or 30 you should read if you want to start to get a really good handle on things. But how many members would actually have the time or desire to read through them all. That is for nuts like me.
