Leaf problem... need help

doing a dwc grow in a 1 sqaure tent onto first week of flowering and lots of the leaves are going like the one in the picture my ppm is 1100 and ph 5.6 using canna aqua nutes... the temps are 25 to 26 and humidity is 68 i have to plants going other is okay its only this one like this its also on older leaves there very dry to touch....

I'm not saying for sure, but I've seen a friends grow appear like that because of spider mites. Check the bottom side of some of the leaves with a magnifying glass.

It doesn't look like a deficiency that I've seen, but take a look here and compare the pics to the rest of your plants: http://www.growweedeasy.com/marijuana-symptoms-pictures

-spek

checked for already and it be on both plants if that was the case and iam from the uk and its a fresh new grow tent and all new stuff mate