Strange Brown Spots Forming On Top Fan Leaves

Maybe calcium issue, maybe something else, hard to tell, so purple. You will want to link your diary to any future questions and try and film them in white light so the colours are accurate. When you do this more people will answer your question as they have all relevant information at their fingertips with out clicking and trying to find it. In your diary you said your getting a new PH meter and the old one was from the dollar store. Your mediums PH maybe off and is locking out uptake of nutrients like calcium. A theory not 100% sure yet. When the new one comes in, calibrate it and test out your solutions PH compared to your old one and see how much of a difference their was. You may also want to look into getting a TDS pen for checking your feeding solutions concentration or EC. If its to high it can also cause lockouts via salt build up similar to PH getting out of wack and can make it look like a deficiency when its not. 5.8-5.9 in veg, 6.2-6.3 in flower for PH values are what your looking for when growing hydro in coir/perlite EC values are bit different as they rise with plant growth. Best Of Luck!