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What is pH?

Yea, the Hanna meter from Amazon (about $28) needs a precision size phillips screwdriver. Use a standard no. 1 or 2 and you'll mess up the screws. Not sure what the big deal is with calibration. I just do mine at the beginning of a grow. My problem is the meter takes about 3-5 min to settle down on a reading. I only seem to get about 2-years out of a meter. Is there a good one for under $30?
 

Dwight Monk

420 Support
Staff member
So why is a pen you need to clean and calibrate better than a strip or a tubed soil test......the whole calibration thing seems like a real pain in the ass.....what if you get it wrong?
Depends what you are growing in and what you need IMHO. Soil is more forgiving than "unnatural" ways like Hydro mediums where you may want a more exact number and not a "looks like it is close to about x.xx PH" (which is all you can get with drops/tape as they are only good for a "ballpark" reading basically). It is a weed after all and not like Mother Nature adjusts the PH and PPM to a certain number before it rains (nor does she only rain a certain amount and a certain way), as the plant will adapt to whatever environment it is in up to a certain point. So some try and make it an exact science to increase quality and yields, as to how much things like that affect it is probably up for debate, as it is harder to have a controlled experiment when two seeds from the same plant will act totally different (even Clones). Along with different strains prefer different conditions (RH, PH, amount of light) and amount of Nutes etc....etc...I mean folks used to grow it outdoors in middle of nowhere in the forest, and once planted they would only come back at harvest time, and they managed to get something out of them, just the quality and quantity potentially lower than in a controlled environment on a plant by plant yield/quality difference. But what do I know ;) :19: as I'm still learning, and probably still be learning until I die.
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016
I only seem to get about 2-years out of a meter. Is there a good one for under $30?
No I really don't think so. But if you're getting 2 years out of a cheap one then you're doing great.
 

4Dutchess

Well-Known Member
Its why they make the 4 calibration fluid and the 7. Its to see if its right. If it reads 7 with 7 cal and reads 4 with 4 cal its acurate. I havent checked mine with the 4 yet. Once you get used to your waters/nutes average PH you know if its off. Good to check with both 4 and 7 calibration. If you need to calibrate use the 7.
 

PurpleGunRack

Well-Known Member
So why is a pen you need to clean and calibrate better than a strip or a tubed soil test......the whole calibration thing seems like a real pain in the ass.....what if you get it wrong?

The litmus strips are useless, they are often 2 points off.

Drops are hard to use after nutes with coulour is added, but a fine for soil growers and a good back-up for the meter.

Calibration is easy and only takes 5-10 minutes to do.



No I really don't think so. But if you're getting 2 years out of a cheap one then you're doing great.
Even top quality probes for professional meters only last about 2 years depending on storage/cleaning discipline.
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016
Hey PGR I talked to you once about probe storage solution. I have a Bluelab combo meter. Most of the storage solutions seem to be KCl. Was thinking about making my own but haven't gotten around to it.

It seemed to me that when I just leave the probe in the barrel of rainwater I use for the plants- it lasts just as well as it does in storage solution- and the ph doesn't need calibrating as often. It's recommended to change the probes after a year anyway. I have a spare - but it's been a couple years and the first probe is working fine still.

You sounded like you have a bit of knowledge on the subject - and said that this storage stuff, which can be expensive, isn't necessary and 'brackish water' would work just as well. Can you elaborate a bit on that maybe? I'm curious about what's behind that statement.

Generally- what solutions would be good for a probe and what would be bad - and Why....and what you meant by 'brackish water'. Thanks!
 

PurpleGunRack

Well-Known Member
Hey PGR I talked to you once about probe storage solution. I have a Bluelab combo meter. Most of the storage solutions seem to be KCl. Was thinking about making my own but haven't gotten around to it.

It seemed to me that when I just leave the probe in the barrel of rainwater I use for the plants- it lasts just as well as it does in storage solution- and the ph doesn't need calibrating as often. It's recommended to change the probes after a year anyway. I have a spare - but it's been a couple years and the first probe is working fine still.

You sounded like you have a bit of knowledge on the subject - and said that this storage stuff, which can be expensive, isn't necessary and 'brackish water' would work just as well. Can you elaborate a bit on that maybe? I'm curious about what's behind that statement.

Generally- what solutions would be good for a probe and what would be bad - and Why....and what you meant by 'brackish water'. Thanks!
Well, I have technician/user level knowledge and a little theoretical knowledge.

The pH-meter works by measuring Hydrogen in a solution, which done by having a glass diaphragm with tiny holes where only Hydrogen can pass through, and a sensor.

Basically any solution with few ions(like distilled water) will make all the H want to merge with that and thus wearing out the diaphragm.
So ''dirty'' water saturated with ions will do, like brown water from a puddle on a field, sea water, stale lake water, snake's blood etc. :)

So ''clean'' water bad, ''dirty'' water good ;)

The company we buy our meters from guarantee 2 years life on their pH probes, but they can be good 4 years or even more if the meter is only used now and again, and kept in storage solution.

If rainwater works, there's no reason in buying the KCl solution, it's there to have an industry standard.
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016
Thanks mate. Reps for that info. Sounds like rainwater is a bad thing to store it in- which I guess I knew already. I have some KCL solution.
Bluelab recommends using their storage solution - which when I finally managed to locate some in the country, was almost $100 before tax and shipping, for 100ml (!!!!!).
Some people/some meters seem to get away with being stored dry. Some of the Oakton pens apparently say they should be rinsed then stored dry. How? I never have even able to store pens dry without them going crazy - but some people do. It's something that seems to cause extra confusion among the already confused users of cheap ph meters. Different sorts of probes? Luck?
:hmmmm:
 

Slowpuffer

Well-Known Member
i use a 20 dollar ph pen, and they work just as good as an expensive ph pen. The big difference is the calibration needs to be checked more often. this is the 2d. one I've used, and like you say, this one advises storing dry with the cap on. I've been using this one for like 6 mos. now, and calibrated it like 3 times, and it's been stored dry in the cap. After you mix the nukes with whatever water you use, that ph reading should always be the same, or close to it. So if your meter is off, then you should know when you check after adding your nukes, if you use the same amount each time. I fine my ppm meter more useful than ph meter. I could grow without a ph meter , after I know my water supply, but having one takes the guess work out !! The bbatterys for my ph meter, cost as much as the meter !
 

PurpleGunRack

Well-Known Member
Thanks mate. Reps for that info. Sounds like rainwater is a bad thing to store it in- which I guess I knew already. I have some KCL solution.
Bluelab recommends using their storage solution - which when I finally managed to locate some in the country, was almost $100 before tax and shipping, for 100ml (!!!!!).
Some people/some meters seem to get away with being stored dry. Some of the Oakton pens apparently say they should be rinsed then stored dry. How? I never have even able to store pens dry without them going crazy - but some people do. It's something that seems to cause extra confusion among the already confused users of cheap ph meters. Different sorts of probes? Luck?
:hmmmm:
I've heard some people say they got a meter that can be kept dry, but never seen one myself.

Some meters can be survive being kept ''dry'', there'll be a little moisture on the probe after use and when the cap is put on, that *could* keep it moist enough.

If you wanna make your own 3mol KCl solution you put 22,368g of KCl in a bottle, add demineralised water until you have a combined total of 100ml - shake until all solids are dissolved(remember cap;) ) How to get KCl I don't know...

Bluelab making their own special KCl solution specially for their meters, sounds like a marketing spin to make people buy their solution.
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016
Bluelab didn't push it at all- was just a little note somewhere in the manual. And I emailed them they said I could actually use any brand of storage solution.
22kg of it in the bottle sounds like a lot- don't know if that's a typo. Anyway- my impression from testing the ppm of the kcl solution - is that it's just a fully saturated solution.
Thanks again :thumb:
 

Slowpuffer

Well-Known Member
Tead bought the $20 variety. It doesn't drift much. Use it, rinse it, store it damp with the cap on. I think it's closer to 2yrs old than 1yr old. When it dies, I'll drop another $20.
My exact sentiments Tead !!
 

PurpleGunRack

Well-Known Member
Bluelab didn't push it at all- was just a little note somewhere in the manual. And I emailed them they said I could actually use any brand of storage solution.
22kg of it in the bottle sounds like a lot- don't know if that's a typo. Anyway- my impression from testing the ppm of the kcl solution - is that it's just a fully saturated solution.
Thanks again :thumb:
Not kilogram, but gram :) 22 kg is like a medium sized dog ;)
 

Weaselcracker

Nug of the Year: 2016 - Member of the Month: Sept 2015, Nov 2016 - Nug of the Month: Oct 2016 - Plant of the Month: May 2016
Yeah I know I tried to get my neighbour's dog into a bottle to make its barking quieter. It definitely was not going to fit in there at all, at least not whole.

So yeah I thought it was a typo, but thanks for clearing it up and I'll definitely try a smaller dog next time.
 
Re: Common household items for ph adjustment

Yup! You've really got to measure the ph to tell what you're getting. Mix in the fertilizer first to tell where it leaves the ph, then adjust as necessary. If you adjust the ph first then add the fertilizer, you'll end up having to adjust the ph yet again to get it right, taking more time and wasting your ph adjuster in the process.
I don't mean to take your comments out-of-context, but pH'ing your water either before adding noots or after adding noots may depend on the recommendations provided for the specific Nutients that you are using and the feeding schedule/directions provided by the manufacturer, no?