Possible nute burn ?

The pH of your feed solution should be between 6.3 and 6.7...as well as the water you use for them. If you keep it within range going into the plants, you don't have to worry about runoff pH and all that stuff. Is your pH meter one of good quality. If not, you need to toss it and order a real one. The cheap ones you pick up at Wal Mart or order of Amazon and Ebay are not worthy of staking your grow on. pH is one of the very important keys to keeping your plant healthy while growing indoor, so it's important that you have an instrument that you can rely on. I tried using a couple of the cheap ones only to realize that neither had worked properly from the start. I broke down and about a BlueLab pen which cost me $80, but reads right every time and is quick. I don't know what's going on with your leaves there, but both pics you show are on old growth. You judge the overall health of the plant by what the new growth is going. Anything you do to a plant when grown in soil is only going to show up around 3 days later on or in the plant. It's not like a hydro grow where if you screw up this morning, your plants could be dead by this afternoon. It takes the plant time to process what you put into it and for it to work itself out on the plant itself. If your plant is the proper color, it's leaves are praying to the sun and the new growth looks good, then your plant is healthy. You will occasionally have die off during the life of the plant and during the flower cycle, the almost shed as they mature and reach the time for harvest. If you're unsure about anything you've got going on, go to the beginner grower threads here on the forum and read through the sticky's posted there. They contain the very basics of how to grow this plant and keep it alive and healthy. Remember these things: Nutes are simply plant food. If you use the proper quality of soil to grow in, the amount of nutes you're going to need to add to your containers will be reduced. Any container plant will need to be fed eventually if it stays in the same container long enough. The plant uses up the nutrients as it grows larger and when they're used up, only then does it need fed. If you use smart potting technique during the veg stage and grow in good grow soil, nutes aren't really that much a part of the equation. We grow in Roots Organics Original and I don't give any nutes until my plants are around 2 weeks from going into the flower room. I give throughout the flower cycle but only at 1/4 the recommended soil dose by the nute manufacturer. If you use very good soil, the soil should do the majority of the work. I've even repotted right in the middle of the flower cycle too. If they're good and healthy, they'll never even show any signs of it but just grab onto the new fresh soil and keep on doing their thing. But the more you grow, the better you get at it and the more you understand the plant and the process. Read everything you can about it and look at pics of other growers work. It's amazing what you can learn by just looking at pictures. TWW