I have the aquaripure it does reduce the nitrates in the tank but by no means reduces the need for water changes. The owner / developer of it and I, had it out at one point on another forum. It was a real cat fight until he asked me to leave the sub-forum and never come back. I politely accepted and then he took one last shot to which I was not able to reply. He was a total A$$ about it.
Nitrates in general can be viewed in 2 ways.
1) as a pollutant.
2) as a fertilizer.
Water changes not only remove the pollutants, but they help re-build the water chemistry that has been broken down by having organics live in a closed environment. Even if you think you are removing a "fertilizer" (say in planted tanks), you still need to rebuild that chemistry and add to it what was lost during the plant growth (ie trace elements etc...).
Can all this be done with fewer water changes? Sure it can. But that is a lot of testing, monitoring, measuring, dosing. Each time you add an extra step it becomes more complicated. The more complicated it becomes the greater the chance of something going wrong.
Use the product as what it was intended for. Nitrate reduction, but don't assume, ever, that it will reduce your need for water changes.
if you follow me, you avoid stepping in the crap that I just did...