Filter floss does trap very fine particles (water polishing) but also clogs quickly.
A few problems arise when using filter floss for an extended period of time:
1. Loss of water flow. Because the floss clogs, the flow rate of the filter is severely decreased and reduces the turn over rate of your tank. It's very important with any filter and esp with turtles that we keep turning the water over so the bio media can do it's job. If we don't pass enough water over the bio media, the ammonia / nitrite / nitrate levels in the tank will build rapidly.
2. When filter floss clogs, it becomes a nitrate trap if not changed frequently. This also can cause issues with PH levels.
3. Floss is disposable. When it's dirty you toss it and replace. Given... a huge bag of polyfill isn't very expensive but it still adds up. The sponges can be cleaned and reused many many many times over before they start to fall apart. (years and years)
Nothing wrong with using filter floss if you're changing it out every week or so. Most people don't want to spend that much time and effort maintaining their large canister filters. The sponge media provided by the filter manufacturer will usually trap all but the finest particles in the water and not impede high flow rate of the filter's pump.
The recommended approach is to run your canister with the media setup you mentioned below for your day-to-day setup. Only when you need to trap extremely fine particles should you then use the optional setup with the filter floss. The idea being, the optional setup with floss is a temporary use case.
I think if you were to give the media suggestion that you quoted a try, you'll be surprised at how clean your water will remain. Those coarse sponges will still trap a TON of stuff. You'll still need to clean your canister monthly... but that's better then having to clean it weekly with floss
Cheers!
