Hagen wants you to buy their expensive media so they can increase their profits

Remember they tell you to replace your inert expensive bio media 2x a year. :/
Following the water flow, your filter media should always be in this order: 1. Mechanical. 2. Chemical 3. Biological
Here's the logic why:
1. Mechanical first is obvious. Remove the large debris so that the other filtration stages don't get as clogged with gunk.
2. Chemical should always be 2nd. Carbon can remove things like chlorine, chloramine, medicines, and toxins that will kill off the nitrifying bacteria in the biological filtration stage. Removing any of this stuff before it gets to harming the bio stage is a good idea. Having the chemical media second also acts as a secondary mechanical filter... smaller bits of crud get stuck here instead of clogging up porous biological media thus killing off some of the nitrifying bacteria.
3. Bio media is last. This media is nothing more than super porous material to house colonies of nitrifying bacteria. It needs to be kept the cleanest to yield the most benefit. This is also your most expensive media in your filter. When it gets clogged & gunked up really bad you need to wash it (or replace it if you follow the manufacturer's word). Keeping this material as clean as possible as long as possible decreases your frequency of filter maintenance, keeps the bacteria colony as large and as healthy as possible.
OR you can follow the manufacturer's advice. Put the most expensive media where it will get dirty and stop working faster. Also replace it 2x a year... yeah that's fun. Oh and if you really don't understand water / aquarium chemistry they (Hagen) will be happy to sell you a bottle of toxic magic potion to cure whatever is ailing your tank.
I'm definitely not saying Kansasslider is wrong, he's chosen to follow the manufacturer's advice. I'm just saying the manufacturer has THEIR best interests at heart and not yours. Also, these are turtles... completely different filtration needs than a regular freshwater fish tank where I'd assume is the sweet spot majority of where their product is used.
Kansasslider isn't seeing a difference because he is disciplined enough to do monthly cleanings. Most of us are a bit more lazy
