Optimum Bloom is designed to supply the needs of your plant during the flowering & fruiting stage of their growth cycle. With enhanced levels of phosphorus, and potassium, Optimum Bloom will encourage maximum flower bud development and fruit yields. GT Optimum Bloom is suitable for use with all hydroponic systems, using any of the range of inert growing media, including rockwool, perlite, clay and coco peat, in both recirculating and run-to-waste configurations.