brown spots showing up on leaves

hi people
so i noticed yesterday my ph was 5.2 and had been so for 2 days. i corrected that but today i noticed brown spots appearing my guess is its ether because of the ph being off or a calcium build up or some sorts of fungi
all the new growth is perky and spot free so i am unsure if its going to spread or not

dwc grow tap water with ppm 230 ish all i add is canna grow A+b so ppm is about 450 to 500
grow room temps stay in ranges
humidity normally around 50/60% ranges
decent air movement

More likely calcium deficiency with the spotting.

hotrodharley said:

More likely calcium deficiency with the spotting.

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well i have stopped using cal mag because im using tap water
i thought maybe calcium getting stuck in the leaves because their not transpiring enough??
do you think i should still be adding cal mag even though my tap water ppm is already high and contains calcium

Kipn said:

well i have stopped using cal mag because im using tap water
i thought maybe calcium getting stuck in the leaves because their not transpiring enough??
do you think i should still be adding cal mag even though my tap water ppm is already high and contains calcium

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More likely it's due to the low pH. Calcium is mostly immobile in the plant. Adjusting the pH should be sufficient . Too much calcium can cause nutrient lockout.

hotrodharley said:

More likely it's due to the low pH. Calcium is mostly immobile in the plant. Adjusting the pH should be sufficient . Too much calcium can cause nutrient lockout.

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that's why i stopped adding cal mag
ill just attempt to keep ph in rage and see is they spread or not