I found this article about hydroponic lettuce that back up my theory.

Lettuce seedlings pretreated with solutions containing either of N, P, K, Ca or Mg at the concentration of 150% strength Enshi-shohou for 48 hours, were transplanted to 50% strength Enshi-shohou solution containing chloramine. Root injury occurred by chloramine treatment with all the pretreatments. After 6 h of chloramine treatment, 2,3,5-triphenyltetrazolium chloride (TTC) reduction activity decreased in root tissues. Growth rate after 10 days of culture was similar with all the pretreatment. Lettuce seedlings subjected to high atmospheric temperature, high humidity, high solution temperature or high light intensity during culture with the half strength Enshi-shohou nutrient solutions for 8 days, were transplanted to 50% strength Enshi-shohou solution containing chloramine. Again, root injury occurred by chloramine treatment with all the pretreatments. TTC reduction of root tissues after 6 hours of chloramine treatment decreased similarly with all the pretreatments. Rate of fresh weight increase after 10 days of culture was similar with all the pretreatments. It was concluded that root injury was induced and growth was inhibited by chloramine, regardless of nutrient solution constituents or environmental conditions prior to chloramine treatment, although the effect of chloramine was modified by these pretreatments
u.g.u Reviewed by u.g.u on . San Diego Growers please need your input This is going to be a little bit of a read but if you are having unexplained yellowing please read on. Little history on my self I have been growing for about 10 years, I have not had a problem to speak of for the last 8 years. Up until a few months ago I was helping 9 different people with there grows as well. So it all started 4-6 months ago. I have been using advanced nutrients for about the last 5 years loved them never had a problem. But after 4 rooms had to be pulled do to the is Rating: 5