ph woes: new meter

I'm tackling ph issues right now and I'm getting frustrated as fuck here. Right now my Hanna combo grocheck reads 7.2 ( I want 5.8 ). I'm running ebb and flow with rockwool cubes in clay pellets. I never presoaked the rockwool as some people recommend, but I can't even get the reservoir stabilized.

Here's my problem: I have a 12 in air stone and a pump sitting in about 10 gallons of reservoir water. When I unplug them the ph drops to 5.6! WTF!? It doesn't matter if they are turned on, only depends wheter they are plugged in or not.. I plug them back in (still turned off) and the ph jumps back up to 7.2.


Also, something else that's been bugging me: when I move the meter around the rubbermaid bin, the ph wanders by about +/- 0.5. Should it matter where the electrode is? And how deep it's submersed?

stco said:

I'm tackling ph issues right now and I'm getting frustrated as fuck here. Right now my Hanna combo grocheck reads 7.2 ( I want 5.8 ). I'm running ebb and flow with rockwool cubes in clay pellets. I never presoaked the rockwool as some people recommend, but I can't even get the reservoir stabilized.

Here's my problem: I have a 12 in air stone and a pump sitting in about 10 gallons of reservoir water. When I unplug them the ph drops to 5.6! WTF!? It doesn't matter if they are turned on, only depends wheter they are plugged in or not.. I plug them back in (still turned off) and the ph jumps back up to 7.2.


Also, something else that's been bugging me: when I move the meter around the rubbermaid bin, the ph wanders by about +/- 0.5. Should it matter where the electrode is? And how deep it's submersed?

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I think I have the same meter as you Hanna 9813-6 with Gro Check. Did you follow instruction on that card that comes with it to calibrate it with the soulition and temps? I have no idea why it jumps when your pump is plugged in, that is weird. When I move my probe around in my rez the PH changes a little but stops back at original reading when not in motion even if i stop it in a different spot then where it originaly rests. Hope someone with more info on this posts would love to hear how this turns out GL man hope all gets sorted out.

stco said:

I'm tackling ph issues right now and I'm getting frustrated as fuck here. Right now my Hanna combo grocheck reads 7.2 ( I want 5.8 ). I'm running ebb and flow with rockwool cubes in clay pellets. I never presoaked the rockwool as some people recommend, but I can't even get the reservoir stabilized.

Here's my problem: I have a 12 in air stone and a pump sitting in about 10 gallons of reservoir water. When I unplug them the ph drops to 5.6! WTF!? It doesn't matter if they are turned on, only depends wheter they are plugged in or not.. I plug them back in (still turned off) and the ph jumps back up to 7.2.


Also, something else that's been bugging me: when I move the meter around the rubbermaid bin, the ph wanders by about +/- 0.5. Should it matter where the electrode is? And how deep it's submersed?

Click to expand...

If you ask me that rockwool is what you are fighting. I had the same problem with my ph once my plant ate up the cube my problems seem to go away. I have made sure to pre soak ever since.

Tcm04 said:

If you ask me that rockwool is what you are fighting. I had the same problem with my ph once my plant ate up the cube my problems seem to go away. I have made sure to pre soak ever since.

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I`m having almost the same problem.What do you soak your cube in?

growingwild said:

I`m having almost the same problem.What do you soak your cube in?

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Best results that I have seen is use ph adjusted water down to 5.0-5.5 soak 24-36hrs then I shake the cubes til they loose most of the water from them try not to squeeze them it closes up alot of air cavities in the rw once they are mosly dry they get the clones inserted rooted and into the ebb n grow. My question is have you looked at the airstone I have had issues with reused airstones raising the ph in my system just a thought.


Hitman40

not sure about the PH meter..I use a diffrent brand..but I will say that PH fluctuated like crazy in small resiz...You have a 10 gallon...Sounds about right...Your probably ph down every day ? other day ?......Bigger resi less PH fluctuation...just my 2 cents..

Should be soaked in PH 5.0 to 5.5 water for a few hours. It is a must to soak them ...
Some say overnight .. Also your issue with the PH reading going up when plugged in . Check your electrical ground..

Even try another outlet to see if it changes. Could be semi grounding in your tub possible pump ground issue may effect your readings in your pH meter

Also make sure you have no algae.... those rubbermaid tubs let alot of light in there . Algae may cloudy water / greyish white. snotty bubbles at water level on the sides of the tub will wreak havoc on PH .. Good luck man

not rinsing the hydroton well enough can also cause problems, i had a meter that would act crazy if it was too close to the lights

When you say cubes... 1.5", 4", 6" or the mini-cubes?

My PPM meter gives wildly differing readings if it is dipped in water with lots of bubbles. I take readings off to the side, out of direct contact with the bubbles to get the actual ppm. Wondering if this is why you are getting the high readings with airstones running.

Someguy15 said:

When you say cubes... 1.5", 4", 6" or the mini-cubes?

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They are in 4" cubes.

GreenThumbSucker said:

My PPM meter gives wildly differing readings if it is dipped in water with lots of bubbles. I take readings off to the side, out of direct contact with the bubbles to get the actual ppm. Wondering if this is why you are getting the high readings with airstones running.

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Actually my gadgets are all off when the ph changes. It's just the act of plugging them in that affects it (the power strip is turned off), and it's mainly the pump. Given that I have electrical problems, am I safer measuring the ph with everything unplugged? I would imagine the pump is messing up the meter, not the actual ph.

problem sounds electrical to me i always remove sample from res. in ''clean-glass' container & then check ph. with no outside interference & i do this before i flood table after i flood table i discard leftover nutes on fruit trees & rosebushes using gh. nutes & drain to waste program so far no problems

About al meters are affected by ek lectrical interfence to some extent. A major interference is commonly electronic ballasts, however some people have some interfernce problems associated with small submersible pumps. One think that will usually stop the problem if it is from the pump is to use a titatium bicycle spoke as a probe for a ground wire. Just wrap a piece of stripped light wire such as speaker wire around one end of the spoke and stick the opposite end of the spoke into the water. The other end of the wire away from the spoke can simply be stripped and attached to the screw that holds the trim plate on your nearest electrical plate. Evem if it does work it shoulf only be considered a cheap r temporary fix. With your resrvoir grounded it basically nullifies part of the protection provided by a GFI power strip.