I went with canna because G-Love had good results with it, iirc he also used a mix of canna aqua with success when he ran out of substra. Treefarmer did just as well with GH so there are a few tried and tested nutes that work with hp aero. If you use one of these initially it`ll be one less variable to worry about.
Do you use canna with the recomended mixture (40ml to 10L, or do you have a custom mix with it?
From a website:
Recommended EC for Substra Vega A + B is 0.8 - 1.5 mS/cm (Part A plus Part B and assuming source water at 0.0 EC)
What scale are they using?
Water gift: 3 - 5 liter / m2 / day
What does this mean?