Clones Recovering - Nutrient Deficiencies Present? [PICS]

A few weeks ago I had some serious problems with a pythium infection in DWC...

I ended up pulling my plants. I chopped off all of the roots and I chopped them up into several pieces and treated them like cloned cuttings, most of which survived. The ones that didn't were simply cut in places that are not conducive to further plant development (i.e. it's really hard to root a single cannabis leaf!)

This is the current state of the clones, and there are 3 new seedlings that sprouted 5 days before this image was taken (see: 5a, 6a, 8a)

Right click on the image and hit "Download Original"

https://www.dropbox.com/s/wz0vpcflcjmknrx/20130628.jpg

I have them in 5 gallon pots with 50% peat moss + 25% organic soil (.1/.1/.1 NPK which is essentially zero) + 25% play sand.

A gallon or two of 150 ppm tap water was run through each pot with significant runoff to remove mobile contaminants.

A half liter of 450 ppm GH FloraNova Grow soln. was introduced to the top layer of the soil, saturating the first several inches of the top medium layer.

I wonder if I have a phosphorous deficiency (purple stem). The purple seems to have subsided a little since I fed them yesterday. I'm not sure if I should feed them again, perhaps with 600 ppm nutrient solution. I don't know how to tell if they are starting to be burned by nutes. I am afraid I an feeding them too little right now. Any and all comments would be greatly appreciated.