If you are confident on your water quality, I wouldn't do wc's. I have not done one since I started the fight with the Kent M. I've not seen bryopsis in a couple of weeks now, but I read where keeping the numbers elevated for a while will be sure its gone down to the last root. I plan on doing a change at about a month and a half from first dose. As long as your testing your other parameters and you see no reason to remove nutrients then I would wait. Something I just thought about as well, when I raised my mg, my alk spiked by about 1dkh, 8.0-9.1. So, be sure you are watching that and your ca. I did not see a change in the ca, but I always check when I am making "chemical" changes.