pls diagnose

i am not sure what is wrong with these upper leaves...4th week of flowering. i recently rid of my low EC solution and replenished with fresh H20 and nutrients. i am watering every other hour, flood and drain. is this plant over watered or fertilized? i am using the van de zwaan hydro plan. the van de zwaan plan consists of parts A and B which are used the entire cycle, B is a NPK soln and A is a calcium nitrate soln. the EC is 1.4 and the pH is about 6.0, the H2O might be a little cold.

Flash might not do pic justice... see leaf in background.

check out this site...scroll down til you see a pic that matches urs- i am sure you will find your answer there. http://www.icmag.com/ic/showthread.php?t=11688

(off the top of my head i would say magnesium def, maybe a lil N too)

phosphorous deficiency?