m0useanswered grow question 13 days ago Plants are looking healthy in the diary. I did notice you are around a PH of 6 and biobuzz says not to go below a PH of 6.2 So I would try and up that a bit if you can. 6.5-6.8 is good IMO. if the nutrients your feeding are fully available then the PH is less important to keep it so low.
I don't see sign of N tox in the diary but in the pics you uploaded here it looks like that a bit. I think that you might need to get some runoff to prevent buildup in the medium. as it can mimic a lot of things. Also would be good idea to track the concentration of the the feeding solution your giving them in EC or PPM, EC is king but PPM also works just fine.
I feel if you give them a small flush of just PH'd water and follow up with a correct feeding it should bounce back. but careful the medium does not get overly saturated as no one likes root rot issues. So do it slowly.
Good Luck!