But most important thing is to test first before dosing. So let’s say your calcium is 420 and alk is 8.4 currently but after a week your calcium drop to 380 and alk is 7.8 , then dosing is not really needed as water change is sufficient to replenish ( take into consideration tank size: so if you have a nano, water change but if a larger tank , start dosing slowly and test constantly until your reach your ideal parameters) Sent from Singapore Reef Club mobile app