Where should my PH be?

Grobo Ph is at 6.3 i use RO water and add nutrients where should my filling ph be at? Drifting up towards the Grobo PH or should I be matching it,

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:crossed_fingers: :crossed_fingers:


I didn’t get an acceptable answer so I will drift up to Grobo’s ph

As @SilverGrobo mentioned in above post, in-between 5.3-6.5 should all be good. Ideal is 5.6-6.0 :+1:


You are still not answering my question

Since you’re adding nutrients I’d say try to shoot for the same pH as the recipe is currently targeting; did you test the res water to determine it was a 6.3?

If you fill at a lower pH the grobo will try to increase the pH. If the nutrients were recently added and haven’t settled or are already causing (an upward) drift I’d expect it could have a compounding effect and might overshoot (and then it’d be consuming some pH down to rectify).

You can mark the 1 and 2 bottles with a marker at their current level and monitor how much of it is being consumed; this should help you to determine how much fluctuation (outside expected parameters) is actually occurring and whether or not you should be matching the pH or compensating in either direction first.


I bought the same meter that Gribo uses that you bought. Both meters show my ph in my reservoir as ph 6.3 1.8 EC,water temperature in 70 F should my fill water be 6 3 or should I let grobo adjust my ph to 6.3 ? If your answer has any numbers in it then you don’t understand my question about nutrient lockout

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If you get your fill water as close as you can to the perfect ph then your Grobo just reduces the amount of nutrients it has to put in to adjust the water. So if your PH is off any your Grobo will adjust by adding the proper nutrients to level it out. If you want to save a little money on nutrients its best to get it as close as you can first.
Hope this is what you meant…


Thanks for answering


Realistically the idea of this machine is that you don’t have to do any of this. As it’s automated and reads the pH every hour, it will adjust accordingly, so you don’t need to do anything. If you want the machine to use less of bottles 1-2 then yeah I guess you can