pH problem?

In coco you need to use cal/mag religiously and generously. But without a diary and/or a lot more info to exactly what you may or may not be doing...........expecting expert advice based on one random picture is a big ask.

The ph always rises in the reservoir you need to add ph down to what you decided

excess and lockout flush and lower the dosage

When I have a problem with my ph being to high I just put a few solo cups full of Fox farm happy from on top of the soil as a top dressing and the ph of the whole pot comes down after your water a couple times. Fox farm happy frog has a ton of humic acid the soil itself has a ph around 4 or so

Low mag… looks like over watering let the soil dry out for a few days… also looks likes its starting to recover from not enough nitrogen. Keep up with what ever nutrients your doing it will come around add some micro nutrients to the mix and let the soil dry out some b4 watering again also dial the light back 20% for a few days when the plant starts to look all perky and good start back in with strong light again. Lowering light intensity always helps the plant recover from stress no matter what the stress is from

The problem here is your introducing feed that can't be absorbed, auto feed isn't the best idea especially from the bottom it's easy to over feed which is happening hete. Give them room to breath. They can grow with only water. Adding too is an art learnt