Marketing again. Back in the day, the idea of biological filtration was a complete mystery to many or most aquarists; the term was not something that was typically heard in non-professional circles. When the UG filter was introduced, it awakened the masses to biofiltration in a way that didn't require them to really understand it in depth, and certainly didn't require them to build or design anything themselves. Open the box, drop the gizmo into your tank, complete the set-up and bang! "Never clean your aquarium again!"
By the time the aquarist came to the understanding that, yes, he/she really did need to do some work, the odds are good that he/she was advanced enough to start to understand the processes going on in the filter. They had to be explained in ways that sounded palatable rather than distasteful. I'm sure that it wasn't an easy sell to utilize the term "bacteria" when selling the idea of UG, but it was done beautifully. Similarly, the notion of these helpful little critters working tirelessly to turn the horrible "ammonia" to the less-horrible "nitrite" and finally to the relatively-benign "nitrate" needed to be sold, and that made the terminology extremely important. Now, it's not hard to make ammonia sound bad; most people have smelled it and know it's not pleasant stuff. But as the fish poo and fish pee worked its way down the nitrification scale, there needed to be a way to describe it that was more-or-less accurate, but which didn't sound too...yucky. The marketing was masterful; nitrate was in! You wanted the stuff; it meant that everything was working to plan.
Maybe the marketing was too good. Today, plenty of folks are happy with nitrate levels higher than are ever seen nature; the fact that these levels don't kill fish right away makes them easier to accept than something like ammonia that rewards laziness with dead fish right nowt. But, when we have "care guides" being written by people who have owned the fish in question for 2 months...long-term success is not on the marketing radar.
