Thanks for answering Mr. Trichome....but I'm afraid I can't answer most of your questions!
Chempak don't make this stuff any more so I can't get the info from their website (I threw the packaging away and keep the 2 part crystals in seperate jam jars!)
The compost doesn't say if it is buffered, but when I adjusted the water in to raise the pH by 0.5 points (with citric acid that I keep for winemaking - not ideal I know, but all I had) the water out kept the same pH so I guess the answer is yes. All the bag says, with undue confidence, is that I won't need to feed for 4 - 6 weeks. True for my flowers in the garden, but never having grown under lights before I am amazed at the growth rate and feel that the nutes in this compost may be used up quicker .
I check the pH with an electronic pen that I zeroed correctly with the 2 buffering solutions supplied.
I do have miracle-gro on the shelf that I use for my garden flowers (N-P-K = 24-8-16).
I kinda like your idea of taking a cutting and hoping for the best with what I have left. It's in its night phase at the moment but will take the pot off the capillary matting in the morning....and yes, when I repotted 2 days ago, a couple of the roots were going brown.
Now that's what I call experience...plant diagnosis across the Atlantic!

Thanks again for the help :thumbsup:

Sawmiller