Hello,
If you go to the hardware store EPA, you will find the "hydroponic sustrate" which works perfect, it's neutral in pH and the pomes rock it brings is somewhat like perlite... It comes with pyth and pomes in 50/50. Pyth is grinded coco coir, so using nutes for coco would be best; they sell also the hydroponic A/B for veg and bud, maybe you wanna use the orchid bloomer 8-12-6 to mix with the hydro B at budding...
After all the research I did I found the best nutes for coco are the ones made by "canna", google it and order thru the web.
TUANIS.