The charts posted by the various companies only apply to their specific line of nutrients. You can not use formulas from other suppliers sites on a different brand. Every fertilizer is different so you have to follow the directions for the brand you are using, ie: General hydroponics application rates will not work with the Canna schedules and vice-versa.
You eventually have to start reading your plants instead of the labels on the products. Good growers do not need pre-printed formulas and rely on the signs and symptoms of the plant to determine when to use additives and fertilizers, not some pre printed schedule on the back of the fertilizer product. The label does not have eyes and does not know the condition of your plants, the ultimate decision to feed or not must rely upon your good judgment and knowledge of plant growth.
Recommendations by fertilizer companies are usually the maximum the plants can tolerate without burning so they can sell more ferts. Anything above 1250ppm in flowering is causing soft rapid cell growth reducing the ability of the plants to adjust to disease and pest pressures and drastic environmental changes.
When it comes to fertilizing, less is best. You can always add more if needed, but if over fertilized it is much harder to remove excessive fertilizer salts once added to the media.
