Lower two sets of fan leaves have gone yellow, lea...

Hey bro! Looks like Nitrogen diffiency my friend, Nitrogen is mobile so it will gradually move up the plant from bottom to top.. You don't want this, especially in veg. Try to raise your N or use some Bio bizz fish mix or garlic beast as a foliar spray, 2ml per litre is good. A couple of times should do the trick. Keep your Ph between 6.3 and 6.8. Water a couple of times with water at Ph 6.5. Then go back to your normal nute schedule. Only water your plants when dry. You'll be fine 😊 Happy growing 😎🌱 Silas