I add 50ml every refill so help or not its not a huge deal. And within that two week time frame it would be kinda hard for me to know at what time to add down so this way it seems to work for my setup. 50ml is cheap, in the scheme of things. But i think were all on the same page here, PH helps plant absorb nutes, if there are no nutes to uptake, ph is a mute point.