Haven't done a water change on my tank for a long time, only relying on red sea no pox for nitrate and phosphate control, last I checked I had 40ppm in nitrate and 0.4ppm in phosphate. Would I do water changes for my tank and if so how often? also my parameters are pretty stable but will the fish benefit from water changes or will it stress them if I do weekly water changes? Am feeding my blue hippo tang nori everyday.