you should always let ph swing up from your starting point to at least 6.3-6.5 if plants can handle it to cover your magnesium intake. If you are than you can bet on trying to use calmag as the spots seem to be a calcium deficiency. Are you using tap water? in some parts of the U.S., especially florida, the calcium in water can be very high. Also the calcium found in tap water is of a different molecular structure and not absorbed well by the plants. Calcium found in hydro nutrients are especially chelated for cannabis and other plants in general and are absorbed well. Your nutrients have calcium in them but if using tap water high in calcium as well it will create lockouts due to toxicity. H2O2 will not prevent lockouts. It simply helps prevent ph rising by making sure no algae can form. You want PH rising and DO NOT want it constant under 6 as this will lockout Magnesium. If you do add cal mag and the problem worsens, I would suggest using r.o. water to eliminate the extra calcium you get from tap. The worse part about hydro is the spread in uptake between calcium and magnesium on the scale. They are at opposite ends which means constant low ph will lockout mag, while constant higher ph will lock out calcium. This is why ph rise is important.
