Yes, i just posted a few hour ago, but i think i might have figured out my yellowing leaf problem.

I was changing my res water and when i looked at the label of the rubbermaid i'm using i slapped my self in the forehead. The container is a 20 Gal/ 76 L container. My growth formula says to use 5mL of solution per L of water (i use a cap full per Litre, thinking its gotta be close).

Having only filled my container a 1/4 of the way i was using 5 cap fulls of solution (thinking 20 x 1/4 = 4 cap fulls, round up to 5 cause they're never truly full cap fulls). I was using the Gallon measurement instead of the Litres! Totally was underfeeding my babies, yet they've seemed to really hang in their... wow, thank god DNF is fool proof.

Needless to say i've now matched the proper feed to the volume of water (76 x 1/4 = 19 cap fulls). I think this will have a dramatic impact on my plant growth, cause i've only really been feeding them a less than 1/2 strength solution! Will keep you updated with photos...