Yes it does rise and no it doesn't rise to unlimited. Over time it rises to a limit.I get that plants will use some of what is in the water but surely, even with weekly 50% water changes, everything will constantly rise?
Use this calculator to see what your dose "accumulates" to.
https://rotalabutterfly.com/accumulation-calculator.php
Here is 7.5ppm dosing alternate days with 50% weekly water changes accumulates to average 50ppm (insignificant) over many days.