BluLab pH pen won't calibrate in 4.0 solution

Soaked the pen in the storage solution overnight and then some, rinsed off in tap water, and ran the calibration in fresh 7.0 and then 4.0 solutions. It calibrated fine in the 7.0, but threw an Er code in the 4.0 solution. Sooo, now it's soaking in the 4.0 solution for a bit and I'll try again later. Nothing left to lose at this point.

TCH said:

After it wouldn't calibrate the 2nd time, she put a brand new battery in it and tried again.

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I had 2 hanna combo meters like that, just wouldn't hold calibration after awhile. I'm using a replacement bluelab at the moment but seems like the QA must've started slipping over the years. Aperra I've seen recommended lately I think?

Calibrate it in PH 7 solution and then try to calibrate it in PH 10 solution instead of PH 4

DCcan said:

Just a good cleaning might help.

Method 1
Soak the electrode in a 0.4 molar concentration of HCl (hydrochloric acid) for 10 minutes, then rinse the electrode with deionized or distilled water. This should remove any organic protein from the glass electrode and the surface of the reference electrode.

Method 2
Soak the electrode in a 3.8 or 4.0 molar KCl (potassium chloride) solution heated to 50°C for 1 hour. Allow the KCl solution to cool down to room temperature, then rinse the electrode with deionized or distilled water. This will open and clean the reference electrode of all contaminants.

Method 3
Soak the electrode in a 4.01 pH buffer solution , heated to 50°C for 1 hour. Allow the buffer to cool down to room temperature, then rinse the electrode with deionized or distilled water. This will open and clean the reference electrode.

Method 4
After each use, rinse the electrode in 0.5 N or 1% HCl. If you have a build-up of oil or protein contaminants, try soaking the electrode in warm detergent and water solution. Degreasing dishwashing detergents or stain removing pre wash pretreatment are ideal for this: any brand will do. An overnight soak may be needed if build-up is heavy. Then rinse the pH sensor in deionized or distilled water and soak for 10 minutes in 1% HCl. Rinse the pH sensor in deionized or distilled water and check in buffers. If the pH sensor calibrates to buffers it can be used in tests. When the pH electrode cannot be calibrated even after attempts to clean it, it must be replaced.

Method 5
For protein removal, soak the pH electrode in contact lens enzymatic cleaner solution overnight. The enzymes will remove proteins from glass and plastic.

Storage
Note: never store your PH electrode in distilled water

• Bluelab uses 4M KCI, Apera uses 3M KCI, others use 1M KCI solution, proper chemical makes it read faster and more accurately and extends service life.
• It is also possible to use a 1:1 mixture of pH 4 buffer and 3..4 M KCl solutions.

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TCH said:

Soaked the pen in the storage solution overnight and then some, rinsed off in tap water, and ran the calibration in fresh 7.0 and then 4.0 solutions. It calibrated fine in the 7.0, but threw an Er code in the 4.0 solution. Sooo, now it's soaking in the 4.0 solution for a bit and I'll try again later. Nothing left to lose at this point.

View attachment 5306644View attachment 5306645

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Years ago I bought a Millwukee MW102 for $115 and gave $85 for an Apera PH60 last year. They work well and I would buy either again.
Both have .01 resolution and replaceable probes. OTOH, the Bluelab sells for about $85, has .1 resolution and non-replacable probe. I've seen reports of failures here as well.


I sounds like your probe has degraded. I accidentally let my Milwaukee probe dry once and it became painfully slow. I was able to rejuvinate it with a soak in hydrochloride acid, might be worth a try. White Vinager can also help.

Some stuff from my notes....

1. Always keep probes in storage solution.
2. Never let them dry out.
3. Never store in RO or distilled water.
4. The probes are delicate, be gentle with them. After use, always rinse in distilled or RO water and keep it in storage solution.

1) 4-8 hours in HCl solution between 0.1 and 0.5 M or 0.3 - 2.1 PH. https://www.vernier.com/til/730
2) Soak in storage KCI storage solution for 30-60 minutes.

Take 21.46 mL of 37% HCL and add slowly in water to make volume up to 500 mL. Final solution will be 0.5M HCL.

.1M =1pH
.2M=.7pH
.5M=.3pH
1 M=0pH

lusidghost said:

I was a Bluelab loyalist for years, but then a new pen and its replacement both died after only a couple of months. The company wanted me to send the pen back and wait like two weeks for a third, so I bought one of these instead. I've been very happy with it. My favorite thing about it is how the display's backlight can be turned on and off manually. That's really helpful when it's down in the res for more than a few seconds.

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I was also team bluelab until I bought a new meter, and paid more for it than my last one. When I got it the readings drifted around like crazy. As soon as you moved it it went all over the map. Brought it back to the shop and they half gave me a hard time about it saying there was water in it .... I used it like 2 times....? My old bluelabs used to get dropped into the tank on a reg basis and never did I have an issue. Finally they gave me store credit and I bought floraflex nutes with it. Then I bought a hanna

Billy the Mountain said:

Apera makes quality pH meters at reasonable prices; $50 - $80 or so

I have a PH60, and have no issues calibrating w/ 4.0 and 7.0 solution; it only takes a minute.

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Went ahead and ordered this setup. Forgot I had a gift card just chillin on my Amazon account from returning the Ecru. Lol. I also have a cheap Chinese combo meter on the way that stays in the res fulltime. Got it for $free.99 through the Amazon Vine program. It will be interesting to see how it stacks up next to the Apera.

TCH said:

Went ahead and ordered this setup. Forgot I had a gift card just chillin on my Amazon account from returning the Ecru. Lol. I also have a cheap Chinese combo meter on the way that stays in the res fulltime. Got it for $free.99 through the Amazon Vine program. It will be interesting to see how it stacks up next to the Apera.

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You should've gotten one of these...



The probes stay in the res full time. I've not really had problems with mine. I've had to change the probe once in 3 years.

Hollatchaboy said:

You should've gotten one of these...

View attachment 5306848

The probes stay in the res full time. I've not really had problems with mine. I've had to change the probe once in 3 years.

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That's out of my budget by quite a bit. Plus I am ready to try a different manufacturer.

TCH said:

That's out of my budget by quite a bit. Plus I am ready to try a different manufacturer.

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As far as the price point, yes... it's definitely pricey, but the peace of mind it gives me is priceless.

As far as trying a different manufacturer, I hear ya. You gotta trial and error everything for your setup. Good luck on finding a pH meter. It's kinda like doing a pheno hunt. Lol

Hollatchaboy said:

As far as the price point, yes... it's definitely pricey, but the peace of mind it gives me is priceless.

As far as trying a different manufacturer, I hear ya. You gotta trial and error everything for your setup. Good luck on finding a pH meter. It's kinda like doing a pheno hunt. Lol

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the only issue I had with this was the price, and having multiple tanks means I need to move the probe around. It is on my wish list for the larger system.

I use pH drops cause the bluelabs always die on me and do Err or don't calibrate in 4 or 7. Real fucking pain in the ass to be honest. Also, those are known to be so fucking off, my friend has the BlueLab Guardian pH Doser and it was reading 5.8 calibrated but when I used drops it was like 6.5 pH. lol he was feeding way too high of PH for the whole first month of flower.

Billy the Mountain said:

Apera makes quality pH meters at reasonable prices; $50 - $80 or so

I have a PH60, and have no issues calibrating w/ 4.0 and 7.0 solution; it only takes a minute.

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My local grow shop switched to only Apera Instruments and doesn't sell anything other than the BlueLab Truncheon anymore. I can vouch they're good devices compared to BlueLab and with the added benefit of replacing the tip of the pens vs buying a whole new pen.

calvin.m16 said:

My local grow shop switched to only Apera Instruments and doesn't sell anything other than the BlueLab Truncheon anymore. I can vouch they're good devices compared to BlueLab and with the added benefit of replacing the tip of the pens vs buying a whole new pen.

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I've had mine for ~ 3 years, it's used daily most of the year and haven't had any problems so far. Like you said, if it does goes bad, a new probe is only $30

Billy the Mountain said:

I've had mine for ~ 3 years, it's used daily most of the year and haven't had any problems so far. Like you said, if it does goes bad, a new probe is only $30

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I owned 3 different pH Pens from bluelab all got Err even stored in their solution and cared for very well, then I also had their soil pH pen which lasted the longest but it died and you can't change the probe unless you have the guardian unit. My theory is they're designed for fail after a year (once the warranty is up) so you gotta dish out another $100.

Same thing happened to me. Mine sat in a storage unit for 7 years, so perhaps that's why it wouldn't calibrate. The battery still worked after all those years and I was disappointed i bought all the calibration solutions.

I purchased an Oakton EcoTester about a year or so ago and its fucking fantastic...

I also purchased the Bluelabs soil pen, It doesn't seem to do what I need it to so I haven't been using it much..

Antidote Man said:

Same thing happened to me. Mine sat in a storage unit for 7 years, so perhaps that's why it wouldn't calibrate. The battery still worked after all those years and I was disappointed i bought all the calibration solutions.

I purchased an Oakton EcoTester about a year or so ago and its fucking fantastic...

I also purchased the Bluelabs soil pen, It doesn't seem to do what I need it to so I haven't been using it much..

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Something interesting you could do is do a slurry test 1 part medium to 1 part water and see what the pH is with the ecotester, then see what the soil pH pen says, those pens are able to be used in solution & soil. My soil pen was "calibrated" but the slurries always gave me entirely different numbers. Going off the slurry always provided better results looking at the plants and noticing faster drybacks.

I must have a odd blue lab. It’s Probly 5 years old. It did have an issues when new with 4 cal but snapped out of it. Has been rock solid. Always cals and is never off more than a couple 10ths. It has gotten slow but stir and give it time and always works.

This isn't giving me the warm and fuzzies over my latest purchase but will monitor. I also use the drops as a backup but some of the additives stain the water color making it more difficult.

I purchased my Bluelab pH Pen 11/10/2015 still runs like a champ.