Go
here, to the BRS website's dosing instructions for 2-part. This should help regarding the order of dosing, and what to expect as a result.
This is a quick excerpt from the website;
Test calcium, alkalinity and magnesium levels and adjust to correct points, as needed. Levels must be at the right points before beginning daily dosing. Use the BRS Reef Calculator during this step.
*Spread the recommended adjusting doses out over a few days to avoid shocking the system. Be sure to dose each solution separately and slowly to high flow areas of the tank. This is especially important when dosing the Alkalinity portion of Recipe 1 as a temporary increase in pH will occur.*
When dosing Alkalinity white flakes or a cloud may appear. This is normal and happens because the solution is highly concentrated. It will dissipate as the solution spreads throughout the tank. Just be sure to add the dose slowly to a high flow area.
Determine the daily dose by starting with the table below. Calcium and Alkalinity will be dosed daily in equal amounts.
Add doses of Calcium and Alkalinity separately and slowly to high flow areas of the tank.
After a few days of dosing retest Calcium and Alkalinity levels. If levels are not on target adjust the dose up or down. It may take some trial and error to get this part dialed in.
Once the dose is dialed in continue daily dosing until the gallon jugs of Calcium and Alkalinity are finished. At this point it is time to dose 20oz of the Magnesium solution. This can be done entirely in one dose just remember to add slowly to a high flow area of the tank.
It is OK to dose the Magnesium portion in multiple doses instead of one dose at the end. If you opt to do this, just keep to the following ratio: 20oz of Magnesium solution for every 1 gallon of Calcium and Alkalinity. (20oz Magnesium:1 gallon Calcium:1 gallon Alkalinity)