Me i would'nt take my ph below 5.8 ,... should always let your water sit for 24hrs (ph'ed!) after the 24hrs you will get a true reading then if needs to go down add ph down , if needs to go up add water not ph up ! (you should have an extra pot of stood water for this),. when u water check ph on the run off to see where you are. It will do no harm to flush your plants at all they will love ya for it!