Nico,
I am not a good example because I don't do waterchanges but once or twice a year on my system. But my system is different in that I am evaporating huge quantities of water. A day like today with high 60's weather and a light breeze and I will replace maybe 20g of water with Kalkwasser. In the summer times that number goes up to 40gallons a day. Plus I have a much larger filtration system than most people.
I also added Bio-pellets for a different reason than most. The majority of people look at Bio-Pellets of a means of reduction.
After talking with the developers, biologists, chemists and researching them I found that Bio-Pellets could also be adding to an enclosed system. My study into the bio-pellets was not to reduce levels into my tank, but that a byproduct of the Bio-pellets was food for the corals.
I knew several people with exceptional systems that had gotten better results using Bio-Pellets in such a manner, so I took the plunge.
But the Bio-Pellets have been a pain in the butt - I have had 4 reactors in the past 18 months of using them. And I have not had luck getting them to consistently flow and not clump. The biopellets are probably the second highest maintenance task on my system. The first being wiping algae. The Reactors seems to clog weekly. And my last round with the Bashsea resulted in it needing to be back flushed every 12 hours.
Dave B