Please help me fix this issue!

Oh just read your feed is 1230 us/cm, 605 ppms, which is your issue. drop your EC down to .8 or 800 us/cm and they should start to bounce back. Sill concerned about the light distance but as I said co2 changes that and I have no exp with that.

My guess is either to much food(whats your EC/PPM) or your light is to close. I am seeing veg distance is 48" for a 7x7, and flower is 30". Your plants are young so I would be at the 45-55" mark. Not sure how co2 would change that but since your new at growing I would scrap the co2 and work on growing a healthy plant, You can get some nice nug's without it.

Ok, if you had thrips amd sprayed them while the lights were on, that's going to be the explanation of the discoloration.... and it's nothing to worry about... leaves won't repair themselves but don't worry about them. I still encourage you to create a diary here... Just start it with this week and then keep it going... :-D Good luck!

@GrowingGrannie @growinggrannie These are photos and they were placed in rockwool cubes for germination on 11-26-22. They were growing but no taproot showed and after a month in the humidity dome I transplanted to rdwc and started feeding GH nutes. The temp has been set to 86, co2 1300-1400, humidity is at 70%, the ec is 1230 us/cm, 605 ppms. I think I had thrips so I sprayed with insecticide soap and been oil mixture during light cycle. (Mistake, I know) and I may have burned em.

First of all, if you're new to growing, you should start a diary here... Diaries are why this site exists! And without them, you can't track your grows and we can't figure out what you've done or not done that might be the cause of problems. Additional information that's quite important is how old the plant is, what kind (auto or photo), humidity, EC.... You're basically showing us a picture of a leaf that looks pretty sad - but I'd really like to see the whole plant... or at least more of it. It looks like it's one of the very first leaves and if they are the only ones showing this problem, I don't think I'd be very concerned... I'd be more concerned if the same sort of discoloration was showing on the leaves above it... You're not telling us what nutes you're using, and in what amounts... VERY important here... Your pH is spot on, so that's not a problem at all.... 68F for your water is a bit too warm, I'd get it down to 62F max... The leaves look, for all the world, like you've got a potassium deficiency starting but that usually doesn't occur on the lowest leaves first... so basically, what I'm saying is that we need a lot more information... We WANT to help - but we need info in order to have a rational basis for our advice...