new growth "yellowish"

My recently re-planted 30 gallon tank seems to be doing fairly well.. I
have a fluorite substrate, dose 3x per week with Tropica Master Grow (5ml
each time), inject CO2, and perform 40% water changes every 7th day... The
plant growth seems to be fine, most of the plants are doing just fine.. The
one concern I have is that my plants look a bit "yellow/pale"......instead
of a nice "lush green"..

I assume what's low in my tank is Iron (it's always been unmeasurable no
matter what test kit I use)... I'm afraid to increase the dosage of TMG
simply to increase iron.......maybe I shouldn't be??


Any recommendations for me??

Troy