wilma "big 4" system help

hello riu..quick question ive just purchased the wilma big 4 system with the 18l pots what i was wondering is if i use coco soil what nutrients do i use on them cause the plants are going to be feeding of the same water and going back into the tank can they reuse the food over a week period thanks...also would it be better to grow in clay pebbles thanks

i use ionic nutrients in clay pebbles with blue drippers in same system. if u use coco use the black drippers. some people change res every week others jus top up personally i just top up.
my mate uses coco with the canna range and seems to like it.