# PH checker



## DaveWatkin (18 Feb 2021)

This might be a really stupid question...

I recently bought a Hanna PH checker and I am aiming to get a PH profile over the next couple of days .

Is it ok to keep the probe emersed for this time? If removed and place in storage solution it then takes a good few minutes to stabilise a reading when used again. Would rather leave it in the tank and just switch on each hour to grab an instant reading. 

I don't see any issue for a short term use like this but thought I would check with those of experience 

Checker is this type: HI-98100 Checker Plus pH Tester


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## GHNelson (18 Feb 2021)

Not a good idea!
Think these probes have a special membrane that needs protecting......in a solution!


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## DaveWatkin (18 Feb 2021)

Oh, have removed now. I assumed a short period would be fine.

Are the PH probes used on PH controlled CO2 systems a different type? Keep meaning to look into those but never got round to it yet.


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## GHNelson (18 Feb 2021)

Hi Dave
Those pH Controller probes are designed to be used for a specific period of time then cleaned and re-calibrated.
I'm not sure if the membrane material is any different from generic pH probes....maybe someone with inside knowledge will let us know


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## dw1305 (18 Feb 2021)

Hi all, 


DaveWatkin said:


> Are the PH probes used on PH controlled CO2 systems a different type? Keep meaning to look into those but never got round to it yet.


You can get <"solid state ISFET pH probes">, but they are quite expensive. 

I don't recommend pH meters, it isn't that pH isn't incredibly important, it is, but it is <"also quite problematic to measure"> in solutions around pH 7 or with low ionic strength. 

cheers Darrel


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## Davey (1 Mar 2021)

Hi Dave

Im my experience alot of pH probes require regular calibration, when I mean regular, I mean just before making a measurement. Sometimes this consists of creating a calibration solution using a tablet and a very specific volume of water. It really depends on the probe though. 
We rinse/wash ours with distilled water.


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## dw1305 (1 Mar 2021)

Hi all, 


Davey said:


> Im my experience alot of pH probes require regular calibration, when I mean regular, I mean just before making a measurement.


They need calibration before every use, they also need to be turned on for a couple of minutes before you take the the reading.


Davey said:


> Sometimes this consists of creating a calibration solution using a tablet and a very specific volume of water.


Yes, assuming it is a meter with <"two point calibration"> you need pH7 and pH10 and/or pH4 buffers.  

<"You can reuse the buffers"> several times, they aren't like conductivity standard solutions, they are <"buffered" against pH change">.

I make up the <"conductivity standards"> for the lab, but we buy in the pH buffer reference solutions, they are time consuming to make, and the bought ones are <"nicely colour coded for student use">.  

cheers Darrel


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## Davey (1 Mar 2021)

Hi Darrel,

Thanks for your message! Great links! I'll be reading up! Can you point me to more chemistry links within the hobby; solid articles/threads on buffering or kH within the aquarium?

Cheers
Dav


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## dw1305 (1 Mar 2021)

Hi all,


Davey said:


> Can you point me to more chemistry links within the hobby; solid articles/threads on buffering or kH within the aquarium?


I think generally there is a <"shortage of properly referenced articles within the hobby">. In the case of the measurement of hardness your best bet is probably still <"the Krib article by Larry Frank">.  

UKAPS has a few threads linked into articles <"about nitrification">, about the <"phytoremediation of waste water"> and how it relates to the <"Duckweed Index"> etc. We have some more <"about water testing"> and <"analytical equipment">. There are plenty more, many of them not within <"my area of knowledge">.

We also have some articles, covering topics like the <"Soil substrate or dirted tank">, <"A brief and incomplete history of aquascaping"> (both by @Tim Harrison ) and <"CO2 measurement using a drop checker">.

cheers Darrel


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## Davey (1 Mar 2021)

Wow! @dw1305 Thank you taking the time to put that together! That is much appreciated!
Now I just need some time to catch up 
Kind regards
Dav


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