I'm 2 months into my first hydroponic grow room. I have 2 garden store variety cherry tomato plants that i cloned off of my outdoor plants at the end of the season. Not sure of actual variety. They are under a 400w HPS and MH on a 18/6 light cycle. They are showing some leaf curl on some of the top leaves on both plants. Is there something wrong or is this a natural occurrence? The tops of the plants get pretty close to the 400w HPS (about 6-12 in.), but i do have a fan blowing right over the tops of the plants and I notice no burning or other signs of disease. Some new growth and some leaves look to have a Mg deficiency, but 90% of the leaves are healthy green.

I'm using 12.4 ml/gal of both Jungle Juice micro and bloom with a supplement of 4.65 ml/gal of GH magi-cal in a RDWC system. Each sight has a air stone. Nutrient cycles 24-7 and the temp usually hovers around 70 F. I try to change the res every week but sometimes it;s more like 2. Nutrient profile (in ppm) looks something like this:

N-174,P-71,K-137,Mg-69,S-33,Ca-230,Fe-4.54,B-.327,Mn-1.644,Zn-.49,Mo-.026,Na-1.7,Cu-.347,Cl-3.89,Co-.016,Se-.001.

My room temp stays around 25 C during the day and drops to 16 C at night while lights are off. RH has been higher lately but have it at around 60% daytime and 75% night time. Roots look very white and healthy on both plants and the leaf curl seems to have no adverse effects on the plants so far.

Can anyone give me a little help.