Hi yeah unfortunatly the off the shelf products just dont work and all that happens is you have no fish in your tank for three weeks then you add fish and they survive if your lucky but most likely some will die and some will get diseases and parasites - bad water quality is basically like an open wound for fish - exposure to high levels of ammonia and/or nitrite can also cause nerve and brain damage - so it really is not a good way to do things.
The reason these products dont work is because the bacteria that they are supposed to hold needs a constant source of ammonia and oxygen and in a closed bottle it can get neither - sometimes people refrigerate the bottles etc which is a good idea but again not always 100% reliable.
The method suggested on here and most other fish forums is the fishless cycle where you add a small amount of pure ammonia and then measure how that level drops through the course of a day as the bacteria in the filter eats it. The reason this ammonia route works is because in a filter that is turning water though and in turn letting any bacteria in there get oxygen its only a matter of time before the bacteria you need to eat ammonia starts to thrive. Ammonia is a chemical that is formed from rotting organic waste which in a fish tank means fish poo basically but you have a few other things that can create it like rotting plants if they die etc. But yeah where ever you have a rotting organic material in water you get whats called the nitrogen cycle which is:
- rotting organic material -> Ammonia -> Nitrite > Nitrate
so all we are doing here is adding pure ammonia and cutting out the need for fish and their poo.
For full guides on how to do a fishless cycle have a look in the beginners resource section.
The bad part of the fishless cycle is it takes about 5-6 weeks to do.... But you can be really confident of success (and by that I mean long term success) of the tank. Also in a tank like that you cant afford the liberties that some larger tanks can with cycling like in a lets say 125 liter tank you could add a school of zebra danios and do a controlled fish in cycle which involves a lot of water changes but you do get fish in the tank early on but then you are stuck with those fish but in a big tank you have chance to have other fish in there but in a Fluval Edge really you want to stick to the kind of fish that you really want, I mean for the sake of a few weeks filling a £100 small tank with fish that your not entirely happy with just seems like a bit of a waste really. Where as with the fish less cycle at the end of it you can add all sorts to the tank and chose some real little gems.
Oh for fish profiles I would recommend seriouslyfish.com lots of good profiles on some of the harder to get fish on the list above but when I say harder to get you would be suprised how easy it is often to get some of these fish. Where abouts are you from?
Hope thats helped
Wills