Plants goin yellow?

Hi im 3 and a half week in flowering (uk cheese) feed them every second day. Using advanced connoisuer and other advanced stuff yet my leaves are goin yellow? My grow room is 12 by 12 foot with 3 600w lights also when lights are off the temp isnt very cold so it cant be that. Any ideas???

you in soil?

Yes i am forgot to mention that. And also how often should i be watering between feeds? And do i even have to water or should i just feed right the way through?

hi tommy you need to water your plants also as feeding usually some ppl think just adding nutes to water gives them food and water but you do need to water in between your feeds usuall method i do is water feed water feed etc etc as if you dont you can get build up of salts which aint good hope this helps dont drown your babies just water em

lift your pots if they feel heavy or are real wet let them dry out. push your finger in a few inches. if its dry it may be ok. mj likes dry feet. im only watering once a week unless i use co2 then it can be more often. your plants will tell you when to water they will sag just slightly. then pick up the pot see how heavy it is just dont let them sag for too long.