GHL pH probe needs frequent calibration

[Reefer911]

Would you mind directing me to the place where I can properly reply? I see the forum but I don’t know where my question is

 

[Steve2020]

Ok I will try that tonight

Did you get a chance to run that ph test?

 

[Reefer911]

No I didn’t, I had to mow…in the dark lol…and it’s in the 40s ha

I’m trying to figure out my multimeter as we speak.

Thanks for checking in. Any ideas on how to work this thing?

 

[Reefer911]

Running the pH test now

 

[Reefer911]

Also strange is that my conductivity probe is incorrect too. I checked it against a hydrometer. It’s off by .0025

 

[Reefer911]

Ok I did the test and with the 9.0 fluid my probe read 9.03, which I can live with. I placed the probe back in the sump in a high flow area after my skimmer and the reading immediately dropped to 7.85 or so and slowly came back up. It’s currently at 8.31/.32. I’m gonna give it overnight to see where it stops as it may still count up to well above 8.3. If it’s still there in the AM I will turn the pump off and see what happens. Although I do know that is what usually makes it read incorrectly.

If I’m working my multimeter correctly, no stray voltage noted. 0.00

 

[Steve2020]

No I didn’t, I had to mow…in the dark lol…and it’s in the 40s ha

I’m trying to figure out my multimeter as we speak.

Thanks for checking in. Any ideas on how to work this thing?

First you want to make sure the meter works. To do this put the black probe in the COM and the red probe in the V which is the hole above the COM. Turn on meter. Select the ACV 200 position. To test the meter first, find an outlet in your home and put the black probe in one of the elongated slots and the red probe in the other elongated slot. The round hole in the outlet is the ground and is not used for this measurement. Depending on your electrical service the meter should read 110-120VAC.
If all is good, to check for stray voltage use the same settings. Unfortunately that meter looks like the lowest setting for VAC is 200. Hopefully the meter displays a decimal point. Put the black probe on a known ground. a ground can be any metal object that has direct contact to the homes foundation. A metal screw on a metal electrical component that is plugged into an outlet can also be used but the screw must not be insulated by rubber or plastic or similar material. If their is no metal object as I described you can put the black probe in the round ground hole of the nearest outlet. If you don't have a close outlet that will reach you can use a 3 prong extension cord pugged into an outlet and put the black probe in the round ground hole. Then put the red probe in the sump or tank water at record the meter reading. Should read 0VAC. I have read that 20-30VAC is not uncommon when a tank is not grounded with a ground probe.

 

[Reefer911]

Thanks for the detailed instructions. Exactly what I needed. I’ll do that in the morning

 

[Steve2020]

Ok I did the test and with the 9.0 fluid my probe read 9.03, which I can live with. I placed the probe back in the sump in a high flow area after my skimmer and the reading immediately dropped to 7.85 or so and slowly came back up. It’s currently at 8.31/.32. I’m gonna give it overnight to see where it stops as it may still count up to well above 8.3. If it’s still there in the AM I will turn the pump off and see what happens. Although I do know that is what usually makes it read incorrectly.

If I’m working my multimeter correctly, no stray voltage noted. 0.00

When you say slowly are you talking within a minute or two or is it longer? Probe should stabilize within a minute. At least my GHL probe does. Previously did the PH drop when you turned the pump off or when you turned the pump back on? Is it a fast change or slow over many minutes or hours? Could you do a screen shot of your ph chart during the time frame of the issue you were seeing? If your not sure how to do that I can help with that.
Tomorrow during your pump test, if the ph shows the same issue you described in your first post, take out the probe, dip it in RODI water, dry it off and put it in the 9.0 ph solution and see what it reads and let us know.

 

[Reefer911]

Last night, from 7.8-8.3 only took maybe a couple of minutes. But the drift up into the 9s can take hours. I woke up to pH in the 6s this AM. But my skimmer was going crazy so that may be the reason for that. However I did place the probe in 9.0 and left it while I delay with the skimmer and it only read 8.45

Previously, the pH would drift when I turn off the pump.

 

[Reefer911]

Ok a couple of screen shots from overnight. The period where pH was around 8.3 was right after I calibrated. You can see the slow drift up over a few hours. And then of course the drop likely to coincide with the skimmer issue. Otherwise I’m confident it would have kept rising because that’s what it does, and it sits at 9.xx

 

[Reefer911]

Stray voltage test following your exact steps shows 0.00 VAC

 

[Steve2020]

Ok a couple of screen shots from overnight. The period where pH was around 8.3 was right after I calibrated. You can see the slow drift up over a few hours. And then of course the drop likely to coincide with the skimmer issue. Otherwise I’m confident it would have kept rising because that’s what it does, and it sits at 9.xx

Downward spikes could be caused by the collection of micro bubbles, then when to much air is collected on the tip of the probe a big bubble will release and the ph reading will go back up. I have seen this with the conductivity probe in the past but honestly not so much with the ph probe.

Question, could yo tell me what connection on the P4 you have the ph probe plugged into? Let me know if it is the second or third from the left looking at the photo.



Is the blue circle when you calibrated? After calibration were your tank lights still on? Do you run a refugium with reverse lighting?

 

[Reefer911]

Yes that’s when I calibrated. The lights were still on but ramping down, blue spectrum of that matters.

No, I do not run a refugium and no lights are on in the sump or otherwise

 

[Reefer911]

I’ll have to check the probe location when I get home this evening

 

[Vinny@GHLUSA]

So when your response to the ticket comes to my email, and I respond on that same email thread, you don't see it?

No because that is a "Do not reply" email as mentioned in the email itself.

 

[YOYOYOReefer]

I would try another probe. It’s good to have several if you are just using these cheap hobby grade probes, Reliable lab grade probes are spendy and they still go bad too.

 

[Reefer911]

I would try another probe. It’s good to have several if you are just using these cheap hobby grade probes, Reliable lab grade probes are spendy and they still go bad too.

The point is that this is a new probe and it never operated properly.

 

[Reefer911]

My Hanna pocket salinity checker measured right on the money yesterday against my TM Hydrometer

 

[YOYOYOReefer]

The point is that this is a new probe and it never operated properly.

i thought the point was to have it functioning correctly. Get a second probe and if it works you prove you’re correct And your new probe is faulty, congrats


If it doesn’t. You should be figuring out what’s causing the interference.

my hunch is its a bad probe or local em interference