Have a small indoor set up with a friend of mine who seems to think he knows everything yet has no answers to help fix thus issue we are having. Currently have a 4x4 tent using HGL 225 R spec lighting, good circulation, temp and humidity are on point. Use happy frog soil and he also mixed in Stoningtin Blend organic & natural growers mix. Am watering every 3 day. Have 3 autos that are about 2 weeks into flowering and 3 photos 27 days old (white widow and diesel) running lights 18 on 6 off. Noticed a few days ago the leaves on the autos have rusty colored spots and "burnt looking tips" and my photos the bottom leaves are turing yellow but the tops look good. My partner says we do not need to feed the plants the soil we have is enough but after some research am thinking there may be a nutrient issue (nitrogen??) of some sort just not 100% sure so am looking for help advice on how to fix my queens up. Lastly ph is around 6.5.