Canna Aktrivator (Trichoderma) is a once only application that adds a friendly strain of friendly bacteria to the rootzone; as the plant roots develop this bacteria develops with them reducing the chance of root problems occuring later in life. It also will help slightly with nutrient availability and uptake.
Canna have used a tried and tested bacteria strain for this product (Tri 002/003) - there are loads to choose from but the strain they went for has been widely researched in the commercial sector and has proven it's effectiveness over many years.
One tub is enough to treat 300 plants, suitable for use in hydroponics, coco and soil.
Further info and usage instructions here.