Thanks so much everyone! I had really lost all hope tbh.
I did a bit of study yesterday and read about nitrogen deficiency… which would make sense I have really fed them since the very very light application of nurse about 3 weeks ago. So I fed yesterday with some high quality bytes at about 1/8 strength.
I have a ph pen arriving tomorrow. I need to test the water run off right?
Thank you all for your comments and help. Amazing and rare to find
@dictionaryoption test the water first, before you run it through the soil. You don’t want to be running incorrect pH water through your soil.
If the pH is not correct you’ll need to adjust it before you water the soil.
Then test the run off too.
Do you know if your pen comes with calibration sachets/solution? Just a warning, if it doesn’t you might find you have to calibrate it before you can use it.
Well done mate, hopefully things will be on the up and up now. Best of luck! 
CJ.
(Sorry, coco OR soil, you still need to check it first)
Thanks CJ - I’ll see how they go this week and update this thread!
@dictionaryoption You have already received lots of helpful advice 
I will say to keep going with them. I just finished harvesting my final plant of my first grow and it was not without issues. I even thought one seedling was dead so I got rid of it. Actually for fun I replanted the brown seedling with a large houseplant. In about a week or so, the little girl popped through the soil! While she was a very small girl, she did yield a surprising 21 grams!
I would not have been able to get to this point without the support of sincere individuals who share a passion for going!
You will get steered in the right direction.
Continued success.