If you are using GH 3-part then 3-part has buffers...And If you put the correct amount of 3-part in distilled water you will be very close to *5.8ph which is the correct ph for hydro.

*I propagate w/tap water from my well, and do not adjust the ph. If you have no roots...Then you cannot hurt the plant with normal water.

So, If you are using just the water for clones or seeds...I would say...Don't add phdown

Otherwise, if you are adding nutes...what nutes? are you using it for?
latewood Reviewed by latewood on . Anybody with pH utensils do me a solid! Hey my pH meter's in the mail on the mail but I wanna get started on my new grow (see grow log), but I do have a gallon of distilled water (which I'm going to put into a sprayer/mister) and some pH down. How many drops/mL of General Hydroponics pH down do I need to put in a half gallon of distilled water to get to 5.5 (around what you should be doing for propagation correct?) Thank you! Rating: 5