Kool Bloom liquid is used from the first week of flower(not transition)all through flowering then the last week(ripening)before flush stop liquid KB and switch to DRY KB .5tsp pg for the last week of flower before flushing. It is very strong, do not use stronger(youll just fry your plants), do not use with KB liquid(again fry plants), and do not use before the last week to two weeks before flush tops. I use Pro-Tekt, CaliMagic, GH FloraMicro, GH FloraGro, GH FloraBloom, Rapid Start, Diamond Nectar, Liquid Kool Bloom, Floralicious Plus, FloraBlend, Flora Nectar, Kool Bloom dry, and Hydroguard for DWC in that order following the GH DWC Expert Recirculating Chart. It is an aggressive feed program for elevated levels of CO2 but I dont use CO2. The strain im growing now can handle full strength, not all strains can without high CO2. If your plants start getting nute burn, cut back to 1/2str and stay there OR in week 3 try going up to 2/3 strength. Week one should not be started until plants recover from transplant. No more than 50ppm nutes durring recovery. I only use hydroguard and Hormex for recovery. It could kill a plant to get nute burn before a plant is recovered and ready for nutes.