Ph buffer solution problems

Boatguy

Well-Known Member
Milwaukee's are fairly inexpensive and pretty accurate imo. Strips are accurate enough to keep my fish alive if you are on a budget
 

1212ham

Well-Known Member
It sounds like you're using a pen that is designed to calibrate to 6.86 and 9.18 solutions and not a pen that is designed to calibrate to 7 and 4 solutions. What pen are you using?
Agreed, wrong buffer solutions. To confirm, I found a photo and a Pancellent manual that indicate the same.

@Duhh I know this isn't what you want to hear, but I'd throw those meters in the trash and get meters that won't drive you crazy. I did that about 5-6 years ago and have no regrets.

This narrow range color chart is good for growers. I hold the test vial against the right side of the chart and get best results in sunlight.
.

Meters that I recommend. If you buy a ph meter used, assume it needs a new probe.


Apare meters from AC Infinity.


I bought two of these used, around $10 each from ebay.
 

Hollatchaboy

Well-Known Member
I use one of these....

Screenshot_20210220-110440_Google.jpg

It's definitely pricey, but very accurate, and easy to store and calibrate. Also I autowater, and I have a res to monitor.

For what it's worth, it gives me peace of mind, that I wouldn't otherwise have.
 

ec121

Well-Known Member
Ok, I'll make everyone cringe here...

When I looked at spending $120 on a pen, I read through everything and the manual stated that the probes themselves need to be replaced every year or two. The probe replacement costs $36. So that meant after spending the initial $120, I would need to spend $36 each year or two.

About a year or so is how long a $15 pen lasts me, and it's usually because I accidently forget to put the probe back in storage solution. I make 3M KCL storage solution using a little bit of a boatload of potassium chloride that I bought for $10; I also use that to make 1413 μS/cm calibration solution for my EC meter.

I test the pH pen weekly and calibrate it whenever the test reads off. Haven't had a problem.
 

Hollatchaboy

Well-Known Member
Ok, I'll make everyone cringe here...

When I looked at spending $120 on a pen, I read through everything and the manual stated that the probes themselves need to be replaced every year or two. The probe replacement costs $36. So that meant after spending the initial $120, I would need to spend $36 each year or two.

About a year or so is how long a $15 pen lasts me, and it's usually because I accidently forget to put the probe back in storage solution. I make 3M KCL storage solution using a little bit of a boatload of potassium chloride that I bought for $10; I also use that to make 1413 μS/cm calibration solution for my EC meter.

I test the pH pen weekly and calibrate it whenever the test reads off. Haven't had a problem.
With mine, I have 2 probes, I switch out every 2 weeks. I take the one out of the res, clean it, and store it in storage solution. Then I calibrate the other one, and put it in the res. They're always on point, and I've used them a couple years now.
 

Delps8

Well-Known Member
With mine, I have 2 probes, I switch out every 2 weeks. I take the one out of the res, clean it, and store it in storage solution. Then I calibrate the other one, and put it in the res. They're always on point, and I've used them a couple years now.
Hmm…

I've been using the same probe in my monitor for 2 ½ years… well, I had been using the same probe until a rat chewed through the damned lead. Amazon got my $80…and I got my revenge!

I calibrate mine when the light blinks and the pend and the monitor are no more than 0.1 off.

The monitor and the pens are reliable enough that I bought their pH doser that was at a very low price (thanks camelcamelcamel.com). My grow is in a 2' x 4' tent with a res that holds 28 gallons so it's inherently stable but the more smarts I have in equipment means the less work I have to do and that reduces the chances for me to muck things up.

Of course, not that I make mistakes…

That's a screenshot from my AC Infinity Controller 69 app just a few minutes ago. Note that humidity plummeted, temp took off, and, therefore, VPD took off. Very no bueno.

Dumbshit me didn't fill the humidifier before lights out last night. :wall:

One reason I use technology is that it can be help idiot proof things. Having been a human and having been around humans for quite a decades, I know that we screw up. That's expected. The problem is that we don't know when we will screw up.

Technology can help "Cut out the 'Aw shits' and reduce the "Oopsies' ".

1702252891788.jpeg
 

ec121

Well-Known Member
With mine, I have 2 probes, I switch out every 2 weeks. I take the one out of the res, clean it, and store it in storage solution. Then I calibrate the other one, and put it in the res. They're always on point, and I've used them a couple years now.
Of course, but the nature of pH probes is they don't last indefinitely, even if you spend $1200 on a lab-grade unit. The replacement probe for that unit costs $80. It's comes with a 6-month warranty from Bluelab. They say the average lifespan is 18 months.

For my personal growing needs, I don't need to spend $400 on a unit or $120 on a pen when the average yearly maintenance costs alone cost more than the average yearly costs of a pH pen that has a nonreplaceable probe. I definitely thought about both the Guardian and a good pen, but it didn't make sense for my needs. That is a killer unit, though.
 

Hollatchaboy

Well-Known Member
Of course, but the nature of pH probes is they don't last indefinitely, even if you spend $1200 on a lab-grade unit. The replacement probe for that unit costs $80. It's comes with a 6-month warranty from Bluelab. They say the average lifespan is 18 months.

For my personal growing needs, I don't need to spend $400 on a unit or $120 on a pen when the average yearly maintenance costs alone cost more than the average yearly costs of a pH pen that has a nonreplaceable probe. I definitely thought about both the Guardian and a good pen, but it didn't make sense for my needs. That is a killer unit, though.
I'm finding by rejuvenating with storage solution every other week, and cleaning and recalibrating, they've lasted longer. I dunno how much longer, but taking good care of them, stretches their expiration date. This being in my experience, im not saying it's a fact.
 

Billy the Mountain

Well-Known Member
Both drops and a quality pH meter give reliable results,

These $15 P.O.S. meters and their clones are wildly inaccurate and their readings can't be trusted.

1702255814473.png1702255920210.png
 

Hollatchaboy

Well-Known Member

Delps8

Well-Known Member
I've always been led to believe that a pH probe, can't be allowed to get dry. Every one of the cheap ones I've ever used, came dry. Right off the bat, I couldn't trust it.
I haven't seen anything that says that they can't get dry - what I've seen is what to do if they get dry. More accurately, it's almost when they get dry.

Check this out.

I don't use my pH pen much so it's a PITA to check the cap and then refill it just to put it away and not use it for a long time*. Instead, I put some nutes in a coffee mug and leave it in there. Been doing that since early 2021 and, just like the probe on the monitor, it's 0.1 units off when I calibrate.
 

ec121

Well-Known Member
I've always been led to believe that a pH probe, can't be allowed to get dry. Every one of the cheap ones I've ever used, came dry. Right off the bat, I couldn't trust it.
Right, letting them dry out will shorten the lifespan of the probe. Almost all the ones I've gotten will have KCL crust on it, indicating they had some KCL solution in the cap that dried out.

That said, my bottled pH calibration solution is +/- 0.01 (I only make my own EC calibration and KCL storage solutions), so I calibrate the pen when I first buy it.

When I stick it into nutrient solution and it shows 5.8 and a pH drop test shows light orange turning to light green and it still reads correctly when placed in clean calibration solution, it's good enough for my purposes. If a couple of weeks later it's still good, then the pen is good enough until it's not.

Of course I don't use drops each time because that would defeat having a pen - I know how much pH adjustment I typically need and if I do that and it needs more or less, then I check the pen in reference solution and calibrate if needed. When it doesn't hold a calibration for at least 2 weeks, I pitch it and buy a new one.
 

Lou66

Well-Known Member
A few things.

6.86 and 9.18 are standard values for pH buffers. So the bottles were most likely mislabeled.

Expensive pH probes are worth their money. You can pay thousands of dollars for them but the 100 bucks range is sufficient for our use.

Ignore the second digit behind the point. It's not reliable.

The lifespan of probes depends on the usage and maintenance. Properly cleaned, calibrated and used only every other day in a clean reservoir you get much more than a year. If on the other hand you do continuous measurement in sewage you have to replace it after a month.

And please calibrate the regularly. They are not particularly stable. I know labs that do it every day.
 

LeastExpectedGrower

Well-Known Member
Hello I have brand new just opened ph 7 and ph 4 Growth Technology brand buffer solutions showing 9.18 for the ph 7 solution and 6.86 ph for the ph 4 solution. Wtf? It's my first time calibration a ph meter but I have noticed that these 2 numbers are the exact numbers of other ph buffering solutions, so have these solutions been mislabelled at the factory or something? Thats too much of a coincidence isn't it or am I missing something here? Thanks for any help.
1702572120388.png
 

LeastExpectedGrower

Well-Known Member
A few things.

6.86 and 9.18 are standard values for pH buffers. So the bottles were most likely mislabeled.

Expensive pH probes are worth their money. You can pay thousands of dollars for them but the 100 bucks range is sufficient for our use.

Ignore the second digit behind the point. It's not reliable.

The lifespan of probes depends on the usage and maintenance. Properly cleaned, calibrated and used only every other day in a clean reservoir you get much more than a year. If on the other hand you do continuous measurement in sewage you have to replace it after a month.

And please calibrate the regularly. They are not particularly stable. I know labs that do it every day.
The real problem is that the meter probably didn't come with documentation for proper calibration. I looked around and did find that the meter wants 4.01/6.86/9.18 for fluids. The bottles are not mislabeled.
 
Top