Spotting on leaves

It does look like calcium or possibly magnesium but I’m gonna say , regardless of whatever action you take.. also bump that bloom up.. your main source of phosphorus is in the bloom nutes with GH so at 1 ml you def don’t have enough phosphorus in the mix. If you break down what you’re putting in as far as NPK it’s something around a ratio of 3.3 to 1 to 3.8 nitrogen 3.3 phosphorus 1 potassium 3.8 Math might not be perfect there but it’s not an optimal amount of phosphorus. I’d bump your bloom up to 2.5 and see how it responds.