First CBD Grow - Dinamed CBD+

Hey I had the same problem before. I grow in kind living soil (highly recommend). I was using distilled water which contains no traces of mineral nutrients. I also didn't pH it cuz it was at 7. When the defeciency appear I changed to tap water left for 2 days with airstone to get rid of chlorine and phed to 6.7 with earth juice pH crystals. Don't use synthetic pH it will kill your microbes in soil. When the pH around the roots jumps up and down, it can stress the plant and cause brown spots to appear on the leaves. Also what can cause this is root problems. Don't let grow pot sit directly on floor and don't let night temps go below 65 roots don't like the cold.