I recently purchased the new Apex to be ready for Trident and had to take advantage of DOS, it should arrive today and my two part dosing from BRS as well. I've been testing daily to see how much my elements drop daily in order to properly dose. Something to note is that I always test at 12am and do each test at least twice to minimize human error as well as test kit error, I'm using API for calcium (just ordered the salifer version), as for Alk and Mag, I use salifer. My Alk seems to be dropping at a steady rate of .3 a day, calcium for some reason dropped on the first day, rose, then dropped which made no sense to me since I haven't started to dose, as for Mag, it dramatically dropped the first day , then slowed down, something else to note is that the first day I started to dose was the day of my water change, I have a nuvo fusion 20G with about 12-14 water, the rest is rock/sand. I do close to a 5 gallons of weekly water change. I will continue to test daily until my next water change to get an accurate idea. Any ideas as to why my Mag is not dropping and my calcium dropped, rose , and dropped again & advice for dosing?