Deficiency or excess?

Deficiency, but if you are sure youre feeding them properly be sure you are correcting the PH (as more people said) this can block the plants to absorb, to correct this asap we can flush the soil, give them a loooot of water at least a liter per liter soil but with the correct PH, let them recover for 3 days and start again the feeding program, only bloom food (as this normally has a small amount of N, enough for bloom phase), and in a week they are totally recovered and the new leaves should grow all nice and green 👍 good luck my friend, note that ph is key to sucess, if this is incorrect you can feed with the best nutrients on the market but the plant is not absorbing these and doesnt gonna look healthy🧐

Ph! And how close is the light

Ok you have a few things at once going on recently from nute burn to potassium deficiency, nitrogen deficiency and various other deficiencies. You issue is in your substrate. you are expecting a mass lock out sure to improper ph in substrate. You should always have a run off. Test that for ph. If you don't have run off every watering, then there is another issue, likely leading to a ph issue. This all works together. Good luck and happy growing 👍

Hey friend , this plant seems locked out , lower nutrients and check your ph wich is propably too low because i do see a magnesium deficciency , dont add more nutrients that will make it worse

Hydrogen peroxide become air and water i ment lol, tired now but you seem to have a nitrogen issue most likely and maybe got from that neutrient lock out thats why its smart to do a clean up in roots a sort of reset of medium

Would try flush her out with hydrogen peroxide then add microboes and bacterias back then cal mag to boost her back, if any issues in the soil hydrogen peroxide Will defently bounce her back its H2020 witch become water after cleaning up