I've only grown a few plants start to finish so my knowledge to diagnose issues is slim. About 5 days ago I started to notice yellowing leaves on each of my plants. Instead of the whole leaf turning yellow only spots on the edges have appeared. I've tried watering less, moving the light further from the plants and cutting back light time to 18/6. (was at 24) and I'm yet to notice the yellowing let up day to day. I use FF ocean potting soil with no additional nutrients and distilled water. I just do it for fun so I'm just keeping it simple. Any advice would be appreciated. Thanks in advance. =)