I have been dosing brightwells carbon for a few weeks now, and did dose PNS probio but haven't recently. I haven't done a waterchange in awhile because I thought that as I was doing carbon I would eventually see nitrates and phosphate go down due to the beneficial bacteria growing, but does the bacteria benefit from water changes, my nitrate and phos have been consistent without change so far, does benefical bacteria take a long time to grow?