# PH Meter



## ScottW (16 Oct 2015)

Hi All,

Has anyone used one of these type of PH meters or can recommend an alternative for around £20 - £40 ?

I have one of the pen ones, but would like one that I can just leave in the tank and can turn it on when required.


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## Ryan Thang To (17 Oct 2015)

don't buy that one. its cheap and don't work at all. false reading. i use this one and it was expensive but its seem like price has drop. you will need to buy solution
http://m.rapidonline.com/Catalogue/Product/51-5153


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## ScottW (17 Oct 2015)

That one looks good actually and yeah your probably right the eBay one is not going to be much better than them cheap pH pens you.  

When you say I will need to buy some solution do you mean for calibration i.e a 4 and a 7 ?


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## Ryan Thang To (18 Oct 2015)

yep yep i use this brand. http://www.amazon.co.uk/gp/aw/d/B00...ph+7+and+4&dpPl=1&dpID=41Fwvmg8MbL&ref=plSrch


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## alto (18 Oct 2015)

note that although

_The *Voltcraft PH-100 ATC is a handy pH meter* with a resolution of 0.01pH._

the accuracy is +/- 0.07 (no specification on precision)

It's still fine for aquarium use, just don't be misled  - though that's precisely what the description intends 
Similarly check for statement of accuracy/precision for the pH standard solutions, also storage recommendation & life expectancy after opening.
Note that if mostly measuring pH between 4 & 7 use those standards, if most pH measurements will fall above 7.0, use 7 & 10 standard solutions for the calibration.


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## ScottW (18 Oct 2015)

I suppose unless you spend £100s or even £1000s on a pH meter then there's always going to be a fairly wide accuracy / precision claim by the manufacturers. 

When a meter is not in use I've read that you should keep them in either a pH Or distilled water ? Could you actually keep the sensor submerged in the aquarium? Obviously then carrying out calibration on say a monthly basis.


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## Edvet (19 Oct 2015)

http://hannainst.com/usa/whitepaper/CareandstorageofpHelectroderev4.pdf
http://mrclab.com/media/uploads/ph_electrode_maintenance.pdf
NO distilled water, KCL solution is best


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## ScottW (19 Oct 2015)

Cheers


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## zozo (21 Oct 2015)

Yes just keep 'm stored with a few drops of nutral (ph7) calibration solution. regularly check if its not dried out. some have a cap with o-ring which is pretty tight, but the pocket ones don't and always dry out after some time, for those it's best to use a piece of cotton soacked in klc solution to store.

i have the best experience with Hanah instruments. Still got one over 10 years old and also the probe is and still working perfectly. No idea if they still make the same quality, but back than it also stated replace probe once a year. 

My opinion, its a fail safe fairytale, just have a new spare probe ready for use, as long as the old one works no need to replace it. you have to check and calibrate regularly anyway.


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## ian_m (21 Oct 2015)

zozo said:


> but back than it also stated replace probe once a year.


Still standard practice. I notice some of the CO2 controllers for aquariums say this as well.


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## zozo (21 Oct 2015)

ian_m said:


> Still standard practice. I notice some of the CO2 controllers for aquariums say this as well.



Funny is, i bought several ones over the years.. And the pocket models discription never said "Buy a new one each year". .

Oh!? ps.. It should be Hanna instr.  sorry..


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