Can I Tell You About My Water And Filter?

I have an Aqua one, and after a couple of issues with the filter pads (not the pump) and reading about stuff on here, I've made some changes.

With the old system that came with the tank, the water was pulled through a cartridge with filter wool and ceramic noodles, then through a carbon cartridge, then through a coarse sponge.

I decided (in my own little way) that this was silly.  So I've ditched the premade (and expensive) cartridges.  I've now put the coarse filter sponge first, then some filter wool and some ceramic noodles, then some more filter wool.

So far, so good I think.  The water certainly appears cleaner, fish seem happy, and my water values are as follows

pH 7.5
Ammonia between 0-0.25
Nitrite 0
Nitrate 10-20

Does this seem like an OK kind of set up, or have I got a bit ahead of myself and I'm about to run into problems?

Interesting!  Thank you, I might jiggle things about again now!