Originally Posted by Rab.C
i have too say it wasnt there until mt last feed. then this turned up
"the leafs are not soft but paper like"
I think they might be overfed. If too much nutrients stay in the medium, it may pull down the pH, which would lock out mobile nutrients.
It's best to keep your pH at 6.0 in coco. You could check runoff, or just water with 0.8 EC total, first with bloom nutrients.
The P in bloomfood will stimulate root development, and a bigger root system will mean more efficient takeup of nutrients.
They may also be almost ready to going into flower and repotting.