i have no problems with salt build up at all mate , i mix my vegging 2.0 on my cf meter , my ph is anywhere from 6.1 to 6.8 , for cuttings and seedlings i use a 1.4 strength vegg mix. i feed when i water and water only when the pots are truely dry . also i use 5 litre tomato pots . i usually water every 2/3 days , i also only give about 700 mls to each plant at a time. (with weed less is more) i using bio bizz coco fibre at the minute butr that purely down to what my hydro shop has in stock. i have used canna in the past with great results. from a 5 ltr pot and a 2 foot plant i can get upwards on 2 oz a plant. also keeping the plants small and trimming off all the bottom branches u end up with big fat colas like u see in the pics above.