So about my tank, It's a 5g betta tank with a few stems of pothos in there, one 25w heater, 2 filters (both adjustable) set to the lowest settings. Now I am well aware that pothos will remove nitrates, but nitrate removal is not the only thing PWCs do. I am willing to do them regularly, but bettas don't have a huge bioload, so don't strip a lot of micro/macro nutrients from the water. Also considering that the water evaporates at a steady rate, and the pothos continuously taking water out of the tank (forcing me to fill the tank, thus adding new fresh water), would weekly PWCs really be necessary if I didn't overfeed, as apposed to every other week? I ask because he gets scared and stresses out half a day when I gravel vac, and want to minimize that.