Hi guys I'm new to this site. I've just began my fourth week of veg and I'm noticing light yellow circular spots on the edges of the lower and middle leaves.. I also have purple stems on the bottom half of the plants. All the new growth looks fine strong and vibrant. Ph. 5.8. PPM 615. (Tap water that has set out 24hrs) House and garden nute line Ebb n gro 6 site bucket system Feeding 1x a day now being that my medium (stg inserts and rockwool) retains water for a long time. Any suggestions?