yeah, my res is a five gallon bucket (i handwater) and after my 6/9 mix in ro i usually need to put in about 5ml of ph down. if youre only doing a gallon at a time, something i liked to do instead of using the ph up or down, was to use superthrive to lower ph and rhizotonic to raise it a bit. i would do this to young plants and seedlings mostly since i was planning on giving them a little does of each anyway. hth
~c
i need to add ph up, and you need to add ph down. is there something wrong im doing with my nutrients? becuase everytime i mix the nutes 6/9 in a gallon of r/o water i need to add ph up (because the ph without beign altered is like 4.5)