Why do I get stunted clones!

1. Type of grow, hydro NFT
2. Type and ratio of nutes or fertz I use earth nutes at the rate of 1200 ppm ph of 5.8
3. Size and location of bulb with timer settings. Each 4' x 8' table holds 32 plants with 2 1000 watt HPS on a mover
4. Age and strain of the problem plants Bigbud, Been growing the same stain for 2 years now
5. Temperatures of nutes, soil, air. Water temp is 68 to 72 Deg Air is 85 degrees with 1500 ppm of co2 with lights on and temp drops to 70 +/- at lights off.

The enviorment is closed, Total control is maintained by a computer (Growtronix). Humidity is maintained at 45%.

I have mother plants of witch I take clones every 2 weeks, Veg them for 2 weeks then into the SOG flower room.

The problem...

I use the same mothers now for 2 years. This problem is not new but I now have the time to focus on it. Why do I always get a few stunted clones each batch? I try and take only large and healthy clones I treat the all the same way. Why is it that I will always get 2 of 3 dwarfs in each batch?

My Thoughts;
1.Its normal
2.Perhaps there is a bad branch on my mother and the dwarfs are comeing from it.
3.I am a dumass and I dont know how to grow.


Looking for your input. Please

A wild guess...
Do all the clones have the same number of nodes below the surface of the medium? What I'm thinking is maybe if you root a bunch of cuttings with 3 nodes and a couple with 2, the ones with fewer nodes have fewer rooting sites and therefore grow more slowly.
How stunted are we talking here? Slowpokey vertical growth, or bonsai like if you have an early rootrot or rootbound problem?

define what you mean by stunted clones please...mine usually take 2-3 weeks to start rooting and 1-2 weeks before i take them out of their cloning chamber and into soil...then they stall for a week or two before growing again as if they're adjusting to their new surroundings. only time i find true runts is during seedling stage but it's not common...