After months of adding np bacto balance I reached a level of 0.02 ppm phosphate and 15ppm nitrate level, the question is whether to stop adding np bacto balance? Or lower a dose and if so how much to lower? I added for months 1.5ml np bacto balance. on the day. My aquarium is 270 liters with tunze doc 9140 skimmer and is based on water exchanges and that's it. In terms of filtering.