Your larger plant - the fat leaves - Indica - you are feeding all of them the same amount of nutrients? You are going to need to individualize them because they are not the same strains and they have different needs. Definitely more Nitro for the big one and maybe even it off for the smaller one. You need more fert in general and water for the larger one. I am not too prolific with hydroponics. I only use soiless. Here are some formulas for mixing soiless from Rosenthal's book that I picked up along the way -

2 parts compost, 1 part perlite, 1 part sand, 1 part lava

3 parts compost, 3 parts sand, 2 parts perlite, 1 part peat moss, 2 parts vermiculite

2 parts compost, 2 parts sand, 1 part perlite

I suggest chicken poo, guano, worm castings, or rabbit poo for the compost. A mix of all of them would cover it. I personally pick up a mix from an organic nursery. It costs a little more but the lady that runs the place is a bad ass mama. Works like a charm. I will be mixing again soon though so the strain does not get too used to the same kind of mix everytime. I want it to be versatile and strong.