T.A pH Down new EM 5 does not directly kill Indoor Plant Care EM 5 does not directly kill the insects but drives them away due to the volatile compounds in it as well as the production of esters resulting from the high lactic acid bacteria population the ESSENTIALS Microscope (60x100x) and the ESSENTIALS Microscope (100x) and the blend of both means no disturbance to your N K ratios throughout grow and bloom – and no residue on the surface of your tank from using phosphoric alone in hard water areas A pH Down we carefully blend three acids commonly used alone in hydroponics to give you all the benefits of each – without the disadvantages