Step 1: Get baseline water parameters, especially Calcium, Magnesium levels. This article explains how to read your local water report.
Step 2: Obtain General Hardness (GH) Reading using a Test Kit. This is necessary to determine your APT SKY Dosage. If you are very certain you have softwater, assume GH Reading to be zero.
Use the SKY Dosing Guide to determine dosage. For the very first dose, Water Volume = tank's water volume. GH Reading is your tank's GH level.
Subsequently, during water change, Water Volume = Volume of new tap water added. GH Reading = tap water GH level.
The best way is to first mix APT SKY in a small container with some water and add the milky solution into the tank.
If you have good flow, you can also add APT SKY powder directly into the tank. It is OK if it covers the plants.