Ph Meter

[Douglas.Curtis]

Cheap probes are sent dry, so using r/o as the only solution negates the entire pro-meter probe gel argument. You definitely keep sensitivity of accuracy with a constant solution... like r/o.

 

[negative37dBA]

Blue lab has been my go to for a couple years plus now. I have a Guardian and a Combo handheld...both work perfectly. Both are kept in solution and monitoring 24/7. I calibrate every month even tho I have never seen a drift. Quality in my opinion. Since Ph is important in hydro I like this brand.
Peace, negative.

 

[growshopfrank]

Just out of curiosity, did you read the reference incorrectly and conclude, incorrectly, I was testing r/o? Or is this a jab at someone posting info contrary to advice you have personally repeated to many people over the years?

The stronger someone believes a lie, the stronger their emotional reaction is to the truth.

No just when i see someone advocating using test instruments in a manner contrary of how the makers advise it makes me suspicious of that persons agenda.
Lets say that we were in an automotive forum and a member posts "the clueless carmaker says the i need to maintain the oil level in my engine, screw that it runs better with the oil off the stick"
That's 'bout how your advise reads from here.

 

[growshopfrank]

Cheap probes are sent dry, so using r/o as the only solution negates the entire pro-meter probe gel argument. You definitely keep sensitivity of accuracy with a constant solution... like r/o.

The flaw in this reasoning would be the lack of PH stability in pure water.

 

[Douglas.Curtis]

The flaw in this reasoning would be the lack of PH stability in pure water.

*smacksforehead*
Talk about flawed reasoning, 4ppm r/o is plenty stable in that it dies not fluctuate much. He'll, it's barely conductive... constantly.

Yes, I passed basic college chemistry.

 

[Ca++]

Go ahead, follow the no r/o advice, go through pens. Have you actually tried it yourself? Over a DECADE of meters in r/o with stunning results says that advice is wrong.

I will take your decade, and raise you one.
Most probes don't arrive in fluid. They have some sealed away as a reference. Something to compare the measured solution with. Our recalibration accounts for changes in this reference fluid. If stored in a strong solvent like RO, ions will migrate both through and from the glass. Changing the characteristics of both.

I used my meter in RO, and messed it up. It just wandered about. It went right off the scale in either direction, as it's reference was gone.
It's really not worth knocking glasses of water over, when you can just put the lid on.


I'm not 100% sure on this sealed away reference solution. Some pics show it behind a porous plug. I think it must be behind a membrane. Which is why they drift and why they can be revitalised. They do dry out somehow, and do like wetting for a while before initial use. However, there does need to be a HO count to be a reference. If RO was used as storage, this hydrogen count would be from immersion in the fluid to be tested. Which would be a weak count. My meter has been near nothing but buckets and tanks and the occasional calibration solution. So my reference is basically tank water now. Which is consistent, but not as strong as the refill solution. So, I guess, with the claim presented, that RO in the reference chamber pulls from the solution enough to get a count. A count great enough for comparisons. However I can't imagine a great deal of consistency. It would look right putting it in calibration solutions again, but measuring other chemical compositions it could be inaccurate.

It's interesting, but getting a bit far off topic. It does explain why the right solution would give a longer service life between calibrations though. As the reference is constantly being maintained. While my reference is perhaps the average of what it's seen that week. Depending on just how that membrane is playing.

 

[Hammerhead]

I use to have bad luck with PH probes.. I would often have plant problems from PH issues. What I found that fixed this is to clean and cal your probes at least daily. At the end of the day store your probes in storage solution or at least in PH4. Repeat every day. Since doing this all my PH issues are gone. My probes are lasting much longer. I would not recommend any prob that is cheaper than 50$. Ive been using Bluelab PROBPHLEAP probes since they got released with great results. There made for both soil/solution. Most everything today is more expensive including PH probes. These use to be 70$.
https://www.amazon.com/gp/product/B07MDDXJ4J/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

FYI...Never store your probes in RO!. It will kill their lifespan. Absolutely no reason for you to use RO as a storage solution. If you don't have any you can use Ph4 cal solution until you can get some.

A simple google search will give you the same advice.
DO NOT soak or store any pH probes in purified water like distilled water, deionized water, or reverse osmosis water since it could cause damage to the pH electrode and the tester could give erratic readings. Rinsing the probes in purified water is a good practice. Just don't store them in purified water.

 

[Douglas.Curtis]

I have a thread around here titled "Let them be wrong." Pretend I linked it here.

 

[Hammerhead]

People can refuse to accept any knowledge posted. It is there for ea of us to choose.

 

[Three Berries]

If your normal testing pH range is only 8.0-5.0, then no need to calibrate at anything but the 7.0. That being said the Alpera pH20 is super easy to calibrate at one, two or three points.

 

[Ca++]

Some meters only have one calibration point.
Two point calibration deals with where 7 is, and how quick the count should change as you move away from that point you tell it is 7. It's known as the slope, which makes sense looking at a graph.
The third calibration point reinforces the others. It's actually a waste of time if you got the 7 and 4 right. However, with the 10, the meter can see three points along the slope, and make sure they are in a straight line. So if your solutions were 6.8 4.1 10.1 then the meter would read properly still. Even after telling it they are 7 4 10 it would read then as 6.8 4.1 10.1 and so three point calibration can find problems with your calibration solutions.

I'm happy with two points. I have spare meters and spare solutions for when I'm not convinced things are right. I have a test tube and indicator solution for when I'm really not happy. I have not gone as far as 3 point, but it is a worthy test of your kit, including fluids.


You can buy a simple meter for $3 from Ali. I got someone a pair of meters for about £10 delivered. This can make $150 on one pH meter seem crazy. However, do you enjoy what you are doing? I know $150 worth of smart phone looks a lot more impressive than a stick with grey LCD 7 segment display. That glass tip at $50 could be a smart phone. However the cost of an inaccurate meter might be a folding smart phone. It's $150 of insurance and hopefully satisfaction when you use it. Which may in turn lead to 3 point calibration, but lets not get ahead of ourselves. We all draw a line somewhere. Chucking away used fluid is painful

 

[pjlive]

I've been very happy with Hanna's Combo meter for the past couple of years. It has a removable and replaceable head, holds an automatic calibration well, is fully submergable, rugged in design, and is capable of measuring both EC and pH on the fly. It's also copact and has a pocket/belt clip attached. I'm never without the darn thing. It's a little pricey for a home grower at around $150 USD on sale, but I'm glad I got it.

 

[martaperales]

Ne ho usati diversi, ma senza dubbio quello che mi è piaciuto di più e quello che use attualmente è il marchio Bluelab. Se cercate qualcosa di più economico, vi consiglio il marchio Milwaukee.

 

[CrushnYuba]

I'm very curious also. Is there really a huge difference? I have used hannas, milwaaukee, blue. Lab. They were all fine. I used to get these 10$ pens that had to be manualy calibrated with a screw. They came from china wet. They all seem like they worked just as well as long as it was used frequently and maintained. I would always eventually end up losing it or something. Leaving it in a hot car until the storage solution leaked and evaporated into a powdery film. After some abuse they would hold calibration for shorter time. But if i treated them well, is there really a difference?

 

[growshopfrank]

I'm very curious also. Is there really a huge difference? I have used hannas, milwaaukee, blue. Lab. They were all fine. I used to get these 10$ pens that had to be manualy calibrated with a screw. They came from china wet. They all seem like they worked just as well as long as it was used frequently and maintained. I would always eventually end up losing it or something. Leaving it in a hot car until the storage solution leaked and evaporated into a powdery film. After some abuse they would hold calibration for shorter time. But if i treated them well, is there really a difference?

Yes there are differences things like temperature compensating,waterproof ,one touch calibration and build quality but if you treat them right they generally get the job done.
Sadly tho its always good to have a back up be it indicator solution or strips for those times that the pen shows a number that is far different than expected. It is always good to double check with a different instrument/method before making huge PH adjustments if your solution is suddenly showing a large change out of range on your PH pen as the pen may be acting up.

 

[Hammerhead]

I got a Oakton AO-35423-01 a long time ago for backup. I remember the probe arrived dry. I had to add storage solution. It reads dead nuts the same as the BL guardians. It's great to have a portable PH meter when needed.

 

[Ca++]

Oakton branded meters are common at lab supply places. I use the phtestr 10. Unfortunately they went from a grey body with screw top, to one with a green inlay and different top. Apera stuck their branding on it also. Mine was on the market years, but the new version was soon out of stock everywhere. If you are lucky you can find a phtestr 30 of the older type, which has the same probe as the 10 and 20, with higher resolution electronics. However, it's well and truly end of line. Spares will dry up. I wrote this out before but think I deleted rather than posting.

The cost and availability of probes is foremost with a meter purchase. You want them for the $50 that a cheaper meter costs. Most people seem to bust them somehow, so raising the replacement cost wouldn't be good advice for the masses. Think of the tip as your $50 disposable meter, and the body as a nice accurate bit of electronics that you keep. A good meter uses a good ABS body you could tread on. While cheap ones are cheap. There is value to be had.

I used to get a couple of years tops out of $50 meters. I was happy enough, knowing other people were killing them every couple of months. I don't think it's all about treatment, but it's a huge part of why they die. 2 months or two years based on treatment alone. My 2 years extended to decades with a better meter though. Treating it the same. Which isn't particularly well. I just use the lid really.

 

[jaapkaru]

I think I would treat myself to that. We have suppliers all over the globe, asking about the same price. I see no gain from chancing some hydro brand to save 30%. Or paying lots more for what's really too good already. Unless you want constant submersion meters. Which is not as trouble free as it sounds.
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