Urgent help needed ! plant issues

I have a dilemma I can clone and veg perfectly with no issues at all lights are T5 nutes are GH 3part. when ever i flower litterally 1 week in they start to turn yellow they are under a 1000hps i use same nutes I have a 55 gallon drum I take care of them flush top it off check ph and ppm what do I do Im losing my mind. any suggestions?

My camera is busted but heres the deal. Lush dark green in Veg.

when i through them in to flowering they start to fade in the middle and slowly turn yellow. Then the leaf tuens like a bright yellow on the outside with a dark green inside. please help.

Pictures would help. It sounds like nutrient lockout or something. How often do you change resevoir? Do you change it right before flowering? Do you ph your water and where is it from and do you filter it and how and what size lights do you use in flower and how close are the lights to the tops of the faded plants?

When you top up the resevoir are you adding small amounts of nutes trying to bring it back to the ppm of a fresh resevoir change?
Do you top it up in that first week?

OregonMeds said:

Pictures would help. It sounds like nutrient lockout or something. How often do you change resevoir? Do you change it right before flowering? Do you ph your water and where is it from and do you filter it and how and what size lights do you use in flower and how close are the lights to the tops of the faded plants?

When you top up the resevoir are you adding small amounts of nutes trying to bring it back to the ppm of a fresh resevoir change?
Do you top it up in that first week?

Click to expand...

batteries charging will take a pic in 15 minutes
thanks you for the fast response

more info (oregonmeds asked some good questions) with the pics would help