Why are my plants yellowing, stunted, deforming etcUpdated 3 months ago

A common cause of yellow leaves is a nutrient deficiency which should be rectified by adding a little more nutrients. Start with about 20% extra and check the results after a few days. 

For any growth problems, color changes, or deformities we highly recommend emptying, cleaning, and refilling your nutrient tank with a fresh batch of water and nutrient. You should also carefully remove any affected plants and discard them.

There are many reasons for poor plant growth or dying plants but the advice above should be where you start. 

If all else fails your plants may have a disease that can't be rectified and as such should be discarded and the system fully cleaned before replanting with new seedlings.