Ro water ph drift

Im in the process of switching to a auto watering so doing some test runs on my ro water but cant seem to keep my water ph down…using silica and did a full mix of jacks 321 ph to 6.0…i put it in a gallon jug with a airstone to see how long it will sit without drifting and 24hrs later its at 6.9. im currently running a waterdrop ro system thats less then a year old and havent even ran 300 gallons through it… any suggestions will be helpful

by chance was the airstone new and had not been purged???


Used the airstone once to soak some banana peels but thats about it

I am going to bet your stone was contaminated…


You dont think even without airstones i should get at least 24hrs with a stable ph

with a clean air stone or without a air stone your nutrient solution should not drift overnight…Jacks has good buffers in it …


That’s what i figured can it be something in my water or can it be the silica

Silca does change the ph but only once it is added and mixed…it should be stable from that point on…unless your Silica brand does not have buffers in it


Im using armor si

Going to do a straight jack mix and see if it holds

that is General Hydro brand right? I use it and it is a stable product


Yea…then im just left with it being my water

let your RO water sit out and check its PH without your nutes…I am positive your Jacks and the GenHyd SI is not your problem…be careful with the air stone reuse it can cause issues in my experience

I realize checking the PH of the RO water without adding anything may not make a good measurement…what is the PPM of your RO water?


Will do the water test… im going to assume my ro water shouldn’t drift

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I have thought about getting a RO system several times for easier use, but I have come to like using the ZERO water filter to get 0ppm water as my base in my hydro system…

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Ro ph is 5.6

and PPM or uS/EC is what?

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Comes up 0.0 ec

well that is better than what I expected from it…so with that kind of EC level your PH is meaningless…so now we are back to the air stone as a very high probability of the being the culprit here…so mix nutes but no air stone is what I am thinking is your next step…what do you think???


You can’t get an accurate reading of PH or TDS with water under 100 ppm. Any liquid under that value will adopt the medium’s PH immediately.

IMO all nutrient lines drift: one of the reasons it’s packaged separately. I normally see a large drift in PH in the first 24 hours but after that it’s pretty minor. Running a larger amount of solution will tend to buffer longer as well.

Silica can be mixed separately and used as PH up. I believe @dbrn32 does this.

Are you mixing your nutes in the correct order? Silica is always first, followed by cal mag then base nutes.