Ro Water And Ph Measurements

[Online Brewing Supplies]

Since starting to selling RO/DI units and using 100% RO/DI water for my brewing ( salts added) I have found great improvements with my beer quality. One thing that I and my customers have found that we were getting great fluctuations in pH measurements of the RO ( de ionised water) H2O.
Well today after pondering if all our pH meters were stuffed "Foles" found this great post below, we are now much relieved

"The pH of RO/DI water is extremely difficult to measure accurately, as the pH measurement is dependent upon the transport of ions. If you have deionized water, there are not enough ions to get an accurate measurement. Standard protocols for measuring pH of deionized water includes adding a neutral salt such as potassium chloride in order to get an accurate measurement.

RO/DI water also has no buffering ability. As soon as you add your sea salt mix to it the water will quickly adjust to whatever the native pH of the sea salt mix is.

In other words, don't waste time worrying about the pH of your RO/DI water."

Old brewer new trick's. Just goes to show that there is always some one out there you can learn from.
GB

 

[katzke]

Why are you worried about the pH of RO water? If you have a good system and the membrains are freash it should be pure as burning O2 and H. Even asking will get people worried about the pH of their brewing water. The pH is of no importance. IT is what is in the water that is important. RO water should be a blank slate if yoy have a system designed to remove everything from the water. If not then it is much more important to get the RO water tested to see what is left in it.

 

[Online Brewing Supplies]

We were really trying to tell why we were getting such strange/unstable pH readings. Looking at it now if you start to get stable pH then its time to change the filters. Its a learning curve and if you dont question things you dont learn.
GB

 

[katzke]

If the pH is unstable then how do you know if it is time to change the membranes? By the time you get several stable pH readings, are you way past it, or just lucky?

We were really trying to tell why we were getting such strange/unstable pH readings. Looking at it now if you start to get stable pH then its time to change the filters. Its a learning curve and if you dont question things you dont learn.
GB

 

[Online Brewing Supplies]

If the pH is unstable then how do you know if it is time to change the membranes? By the time you get several stable pH readings, are you way past it, or just lucky?

We do a simple titration for Calcium ions. I think this is the proof you need to say when its time to change the DI filter.
GB

 

[MHB]

Get yourself a little conductivity meter, they are cheap as chips (well compared to other instruments), you can get them calibrated in siemens (well milisiemens) or TDS (total Dissolved Solids) usually calibrated against KI (potassium Iodide). Available through Hydro shops, just watch the range some of the really basic ones aren't too good at low salt contents.
I remember long ago studying chemistry, when we were making up standard solutions to stick into the ICP we had to test the water to make sure it was about 0.1s/cm² before we could use it. No need to be that pure but conductivity was the standard method.
Ca by titration, Jesus that takes me back, I'm hunting for a good Ca ISE, these days you can get multi function instruments pH, ISE and Conductivity with ATC in one shot.

Couple of links http://en.wikipedia.org/wiki/Conductivity_meter http://www.lenntech.com/applications/ultra...onductivity.htm http://www.lenntech.com/applications/proce...lised-water.htm
MHB

 

[Online Brewing Supplies]

Thanks Mark
They are some great brain food links which will take some digesting. I have bookmarked them for later. :icon_drunk:
We have been doing the Titration because the kit cost about $20.00, lasts forever and only takes minutes to complete. My next purchase will be a good DO meter (= expensive) then a conductivity meter. Its just a case of where do you stop buying things that go bing !
GB

 

[MHB]

Where to stop I'm the wrong one to ask self described third generation hoarder, with all their **** to.

Bunch of Conductivity Meters on eBay some around $40 look OK, so not in the DO price range but should do the job.

Mark

 

[Online Brewing Supplies]

Where to stop I'm the wrong one to ask self described third generation hoarder, with all their **** to.

Bunch of Conductivity Meters on eBay some around $40 look OK, so not in the DO price range but should do the job.

Mark

Ok , which one would you buy given a budget of say $100.00 ?
GB

 

[MHB]

Value for money the US made Hanna instruments are good. This is the one I have my eye on Hanna Instruments HI 991404
MHB

 

[Online Brewing Supplies]

Value for money the US made Hanna instruments are good. This is the one I have my eye on Hanna Instruments HI 991404
MHB

This cheaper one looks to be ok. For the price its got a lot of features. HERE
GB

 

[MHB]

Having a bit of a stickybeak around the site Want one of these, shame about the price

Yep the hand held look the goods, we have probably both broken enough toys over the years to choose the waterproof one.

M

 

[levin_ae92]

Another thing to keep in mind is if you try to read the pH of RO water, the KCl in the probe will start to pass through into solution (see molecular diffusion) and your pH meter will lose its accuracy and eventually be ruined.

 

[Leigh]

Another thing to keep in mind is if you try to read the pH of RO water, the KCl in the probe will start to pass through into solution (see molecular diffusion) and your pH meter will lose its accuracy and eventually be ruined.

The KCl solution in the probe of a pH meter should be replaced periodically, as diffusion will take place in most solutions, both in and out of the probe...

 

[levin_ae92]

exactly right, but when its not being used it should be stored in a concentrated solution of KCl to extend its life

 

[Online Brewing Supplies]

So a refillable probe is better than the sealed units ? basically what I am asking is, can I regenerate my probe if I replace the liquid. I store all my probes in storage solution.
GB

 

[MHB]

Been thinking of doing it for a while, a better pH meter has been on the wish list long enough.

After reading the specks I finally decided to bite the bullet $400 landed but ATC to over 100^oC, all up I think it's very good value.