ViaBloom flowering supplement is designed to be used in addition to your complete bloom formula. During flowering and fruit set, plants put a significant demand on Phosphorous and Potassium. If a complete bloom formula is used to maintain ample levels of these elements, all other elements included in the formula run the risk of reaching toxic levels. Particularly useful during the last half of the flowering phase, Via Bloom should be used in between tank changes (every three or four days in a heavily flowering crop) to elevate P and K levels. Whenever nutrient is mixed up from scratch, the complete bloom formula is used. Soluble powder.