Lets talk about pH testing.

[aisach]

DOER

BlueLab pH Pen

The manufacturer discusses the checkmark indicator and how to keep the tip wet.
Looks like you will need to get some KCl solution for the cap.

http://www.getbluelab.com/site/bluelab/files/Product Manuals/pH Pen/Bluelab-pHPen-ManualENG-MAY13.pdf


I stated before that rinsing with RO or DI water is the way to go. Manufacturers apparently advise against it. I think they are being conservative; giving that advise because they don’t want users to think that DI water is ‘good’ for the electrode (hence, no soaking). We did this routinely with our probes, quick rinse, dab, on to the next solution. It just takes a few more seconds for the reading to stabilize. But if you are uncomfortable with that, use a pH neutral solution like mineral water, or tap water. Buffer is too expensive to use as a rinse.

If you have probes that DO work and are unsure how to keep them wet. Only the electrode needs to be submerged. A small jar that wont tip over will work. Yes you have to keep an eye on the fluid level and do a dump and refill on occasion. Or wrap the top of the jar with a double sheet of plastic wrap and put a hole in it the size of the probe/pen. Use a rubber band to seal around the top of the jar.

 

[Doer]

I did that. Followed all the instructions. It looks like you always start with 7 and then go to 4 or 10.

10 pH is all that is left without taking the battery out for a reset....if that will reset.

Just read some posts and watched vids, etc. Mine is broken and maybe the Hydro store will swap me today.

The company will say it is self life problems and the 'trode dried out.

Hmmm....aisach, That is a bit more detailed, upgraded manual that I have seen.

Now they don't mention tap water for storage or hydrating. Only KCl. But, the don't mention the concentration.....do they?

 

[spek9]

i got a cheap yellow hanna look a like from ebay for 8 bucks and its tried and true.

ive had it for about a year and its only really been off .1-.3 every time i calibrate. I keep the end in the ph 7.0 or 7.1 calibration solution when its not in use.

at first id calibrate it every week or so because it was so cheap. but now i go 3 months without calibrating and its rarely more than .2 off.

heres the same one i got, but probably not form the same ebay seller: http://www.ebay.com/itm/LCD-Display-Digital-PH-Meter-Measure-Tester-Pocket-Mini-Pen-Aquarium-Pool-Water-/140869621533?pt=LH_DefaultDomain_0&hash=item20cc7bd71d

mine was from china but this seller probably just buys em in bulk and sells em for faster shipping times.

I have the exact same one and for about the same length of time. I too used to calibrate weekly, but I've never been off by more than 0.1, and I calibrate at the beginning of every month now. I've even submerged the entire unit by accident, and it's also suffered a 15' fall off of my balcony to the concrete below and she just keeps doing The Right Thing.

-spek

 

[kinddiesel]

don't want to get to technical about ph, ph to high no good , ph to low no good. ph in the middle very good ,

 

[budbro18]

I have the exact same one and for about the same length of time. I too used to calibrate weekly, but I've never been off by more than 0.1, and I calibrate at the beginning of every month now. I've even submerged the entire unit by accident, and it's also suffered a 15' fall off of my balcony to the concrete below and she just keeps doing The Right Thing.

-spek

hahaha i feel it. ive dropped mine in a gallon of nutes i was mixin and it still runs good.

 

[aisach]

Now they don't mention tap water for storage or hydrating. Only KCl. But, the don't mention the concentration.....do they?

Sorry that your probe is crapping out. Its frustrating when you have equipment trouble.

KCl storage solution is generally 3M to 100ml, thats 3 molar. You should purchase it this way from Bluelab, Hanna, Fisher Scientific, Cole Parmer, Hach, or your local hydro store can order it for you. I would not suggest making it from scratch unless you have a precision analytical scale and a stir plate.
PS 3M=22.368 grams crystaline potassium chloride to 100ml DI water. A plastic disposable pipet is all you should need to drop it in the probe cap. A lot of hydro stores carry those, or can order for you. Or ebay, Amazon.


I found a publication from Hach that has awesome pictures. Just remember to take the info 'generally' since they mean it for their own equipment.


https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CE4QFjAC&url=http://www.hach.com/asset-get.download.jsa?id=11147536803&ei=3Gr9UfmYA6jeigLCvoDYBQ&usg=AFQjCNEuXWiIheGdoPIK5MDJCjBcj_LvmQ&sig2=jBs-asmX2_VO914RKog5_w

 

[aisach]

Im going to order one of those Hanna pens and check it out. Haven't used one of those yet. Cool. Lots of endorsements for those here.

 

[Doer]

Sorry that your probe is crapping out. Its frustrating when you have equipment trouble.

KCl storage solution is generally 3M to 100ml, thats 3 molar. You should purchase it this way from Bluelab, Hanna, Fisher Scientific, Cole Parmer, Hach, or your local hydro store can order it for you. I would not suggest making it from scratch unless you have a precision analytical scale and a stir plate.
PS 3M=22.368 grams crystaline potassium chloride to 100ml DI water. A plastic disposable pipet is all you should need to drop it in the probe cap. A lot of hydro stores carry those, or can order for you. Or ebay, Amazon.


I found a publication from Hach that has awesome pictures. Just remember to take the info 'generally' since they mean it for their own equipment.


https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CE4QFjAC&url=http://www.hach.com/asset-get.download.jsa?id=11147536803&ei=3Gr9UfmYA6jeigLCvoDYBQ&usg=AFQjCNEuXWiIheGdoPIK5MDJCjBcj_LvmQ&sig2=jBs-asmX2_VO914RKog5_w

Update. Pen swapped and tested before out the door. Friendly, neighborly Hydro Store.

Can't do that online, now can we, boys?

 

[Doer]

don't want to get to technical about ph, ph to high no good , ph to low no good. ph in the middle very good ,

No doubt, kindleD. Very good point. Folks should know we are only futzing ABOUT the tools, we are not futzing WITH the pH. And we thank you for that.

We have to know what it is, not hold it at an exact point. We need to monitor the range, not freeze it in place.

Understood.

 

[jondamon]

We have to know what it is, not hold it at an exact point. We need to monitor the range, not freeze it in place.
Understood.

I like how you've worded that!


Agree completely.



J

 

[Doer]

Sorry that your probe is crapping out. Its frustrating when you have equipment trouble.

KCl storage solution is generally 3M to 100ml, thats 3 molar. You should purchase it this way from Bluelab, Hanna, Fisher Scientific, Cole Parmer, Hach, or your local hydro store can order it for you. I would not suggest making it from scratch unless you have a precision analytical scale and a stir plate.
PS 3M=22.368 grams crystaline potassium chloride to 100ml DI water. A plastic disposable pipet is all you should need to drop it in the probe cap. A lot of hydro stores carry those, or can order for you. Or ebay, Amazon.


I found a publication from Hach that has awesome pictures. Just remember to take the info 'generally' since they mean it for their own equipment.


https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CE4QFjAC&url=http://www.hach.com/asset-get.download.jsa?id=11147536803&ei=3Gr9UfmYA6jeigLCvoDYBQ&usg=AFQjCNEuXWiIheGdoPIK5MDJCjBcj_LvmQ&sig2=jBs-asmX2_VO914RKog5_w

Thanks for all the science, I indeed follow, but can't bother with. I'll just get some BlueLabs.

Cool pen. I really like it now. The trick is as someone said to let it read the temp. And it help if you are not holding the small shot glass and raising the temp.

I'm getting several stages of growth in various tents and tub, buckets, flats. Nice to have the Pens...I have EC Pen also, along with the Tri-Meter, that has little D-9 pins. I'm was always bending them. So, it never moves. It's on a big heavy WART for power, iac.

 

[aisach]

Thats great. Glad you got it taken care of.

Knowing and monitoring the range is critical, and having an instrument that you can trust.

I'd have mentioned the temp change in a small volume, if I'd known. Yes temp will change the pH by a tenth or two.

Information never hurt anyone, and you know its here if you need it.

Most growers don't want to bother, and I can relate, but it's nice to know you have options and resources.

 

[budbro18]

Anyone look into making a ph meter out of an arduino?

Ive seen people make fully automated systems with them for relatively cheap.

check out this one: http://arduinogrc.blogspot.com/2011/09/here-is-my-arduino-based-grow-room.html

Ive seen alot prettier versions of them but these are all i can find right now. The one i saw once had controlls to automatically adjust ph with ph buffers, ran fans and a/c at certain temps, and added nutes at certain ppm.

 

[budbro18]

http://www.uk420.com/boards/index.php?showtopic=324655&page=2

another decent one on a grow forum

 

[aisach]

The small amount of lab work that us growers do is important to us. And there is a need and a desire to understand it.
While the details of testing and measuring are minutia to some, the devil is always in the details.

There are those of us that are picky how we do things, even if it is only a few times, till we get the hang of it.
This is the area that I can contribute to in RIU. We all have our niche.

Municiple water delivered to the home, tesing for temperature, pH, chlorine, etc, and maintaining and troubleshooting test equipment is my niche.
There's a lot of bad info out there.

My 'teacher' refuses to adapt his methods to incorporate new ideas and techniques. Works for him just fine.
Me, I like to remodel and upgrade. Works for me just fine.
Just sayin.

 

[Sir.Ganga]

Great thread people....everyone should have at least the basic idea of PH. Its a ritual in my garden and I do see a difference.

My 'teacher' refuses to adapt his methods to incorporate new ideas and techniques. Works for him just fine.
Me, I like to remodel and upgrade. Works for me just fine.
Just sayin.

Ya! You get that type of people here also! Be careful of info on here and double check everything.....AGAIN nice read. Thanks.

 

[Mr. Outdoors]

I have a blue lab. My first went bad after 6 months. I was told it was from trying to pH R/O water. They said that there are no minerals in R/O water, so when you put the meter in R/O it sucks the minerals out of the stone in the meter. They said when pHing R/O water you should always add a little Cal/mag or something into the water to keep this from happening. They replaced the meter for free.

 

[aisach]

Thats great. A new meter and some info to go with it.
Super clean water wont stabilize, and it'll ruin the bulb. We had to pH our RO/DI water for one of the tests in the lab. Stuff just keeps dropping.....
But we maintained our probes to the max. Filling solution, cleaning solution, 3 point calibration plus a 4th buffer to verify, and storage solutions. And replaced as necessary. Each of our probes were several hundred dollars, and meters near a thousand, so it was critical to document proper maintenance.

Yep gotta add ca/mag to RO water.
Just remember that the cheap meters most of us use don't live forever no matter what we do. They're disposable at best.

 

[aisach]

Great thread people....everyone should have at least the basic idea of PH. Its a ritual in my garden and I do see a difference. Ya! You get that type of people here also! Be careful of info on here and double check everything.....AGAIN nice read. Thanks.

Thanks. Love the arches. Very clever. LOL

 

[gnhsgjian]

what might that be then?