Hey,
I would not say that this is insufficient but personally, I prefer high volumes of exchange water instead of slowly but surely increasing concentration levels.
Actually, the ratio between the final top point (called limes in mathematics) and the constant inflow c only depends on the amount of water changed. This means that for whatever substance you want to know about the Limes, you can always take your c and multiply it by the corresponding limes (4 for 20% water change, 1.5 for 60% wc…)
So I think with the really diffficult paros we should be aware that large waterchange ratios will be dangerous. BUT: the same thing we have discussed above can to a certain extert also be applied for germs! And we want to keep the concentration of germs low. Assuming a linear growth for germs is reasonable since low ph effectively slows down the reproduction rate of the bacteria and fungi so the natural exponential growth is pushed down. And it is mainly a high germ pressure that kills young eggs and fry of paros…
I let everyone decide for themselves how much water they want to change but it can help a lot to understand the models available for the description of our nature and aquariums