Young plants having serious issues!

I haven't posted in a while so excuse me if this is janky! I have 3 plants of an unknown strain, growing indoors in a homemade grow tent. Using black magic coco/perolite mix, 1 3/4 tsp mad farmer fert, 1 tsp black magic calmag, 1tsp liquid kelp, and GH ph down per gallon. The biggest is doing great, but I cloned two little branches and they took off fine, but they've been getting worse and worse and I'm not sure what it is! Posting pics of the two of them, they are like 5 weeks since cloning

It's tooo much nutrients or the dirt is too hot meaning it loaded with nutrients.....

standard to advanced nute burn

trash or potup to a 50/50 mix of quality soil and perlite or clean river sand

no nutes ever

good luck

Thanks for your replies guys! I took them out of the coco they were in, knocked off as much as I could, and put them into new coco in a cup with better filtration. I watered with a little cal mag and a normal dose of the kelp extract to help with rooting. The smaller one is doing great and has taken off, but I'm quite sure the other has died. What should I do to help her grow? I haven't added nutes but I was thinking I should move her closer to the light. She's about 2 1/2 ft down from the light which isn't super strongm, just a little grow light I got from Home Depot.

Do not feed kelp that often. Once every 2 to three weeks is enough.

Things look overwatered too (means watered too often, not too much).