With regard to the "don't use store-bought bacteria" -- I have used Seachem's Stability with great success in the past and never lost ONE fish in the process. I recommend the utilization of such products when a brand new tank is being established and someone needs to get fish into it right away (for example, a transfer from another tank)...but they key is using it RIGHT: These products, contrary to what most people think, are NOT designed to cycle a tank automatically for you. They are supposed to "kick start" the system so bacteria can begin to grow and also bolsters and de-shocks the water so fish don't succumb to the dreaded "New Tank Syndrome." That said, what I normally do -- even though Seachem states this can be done immediately without waiting (not sure what other products such as Tetra's SafeStart claims) -- is run a Stability treatment for at least three days so the water definitely starts to "prepare" and then add fish slowly and carefully (i.e. no netting). The key also is to finish the treatment for the length Seachem advises -- normally a week.