I recommend creating a bacterially favoured tea. The linked thread on the Organics homepage refering to Soil Food Web gives you the perfect explanation.
You want to start getting the microbiology of the soil kicking so that the breakdown of the organic materials can be hastened. The plant has the ability to adjust the microbial life in the soil to suite its needs, how fast that happens is tied to having the right baceteria and fungi in your mixture.
If you really want to get good results I will go with this:
I used something similar down in South Africa and its game changer.
Another thing that will help is adding humic and fulvic acid to the mix. I cannot repeat the scientific reasoning but I was listening to a talk and it was mentioned that this helps "balance out" soil.
I use both on a weekly basis and my plants are exploding.
I would also recommend a type of fungi innoculation. I prefer trichoderma but most people use Mycorrhiza. Either one will work. This will also add to the plants ability to adjust the soil to its liking.
Are you throwing salt based nutrients into your medium? Are you dechlorinating your water/using R/O water?