recalibration of tds meter

[trevor peacock]

I've got a hm digital TDS-EZ hand held water quality tester, I've searched the website and googled it but can't find out how to recalibrate it.

Anyone know?

 

[Iron Giant]

I've never needed to, is there an issue or reason you need to. 

 

[Chris Finley]

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F232825880695

 

[Tango]

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F232825880695

Surely that will only confirm that your meter is correctly matching what the bottle states - but doesn't tell / show you how to recalibrate the actual meter.

 

[spruce]

On my tds meter I have a hole in the back just above the pocket clip. When using a small flat electronics screwdriver I can locate the adjusting screw and turn it either clockwise or anticlockwise so the digits on the screen match the tds of the test fluid.

Its good practice to replace the batteries in the tds meter before adjusting the meter as a weak battery could well distort the tds readings.

Its also good practice to dip the test elecrodes in pure water before testing to ensure that you don't contaminate the test fluid.

 

[Tango]

Sir spruce you should be knighted.

 

[spruce]

Sir spruce you should be knighted.

Its only because I've done it myself before. Its no big deal; honestly.

Found this

 

[Tango]

I didn't know the hand held ones could be recalibrated - hence my comment lol. Just looked at mine and sure enough, there's the adjuster - thanks for that

 

[spruce]

I didn't know the hand held ones could be recalibrated - hence my comment lol. Just looked at mine and sure enough, there's the adjuster - thanks for that

Somewhere someone posted a 'how to' instruction sheet on making your own tds testing fluid with pure water and salt. I haven't found it yet, but if memory serves me a certain measurement/amount of salt in pure water will produce the tds reading of 342ppm. It makes that bottle of testing fluid rather expensive.

 

[spruce]

Here is what I was looking for. Its a post to a chemical forum some 11 years ago. I'm copying relevant parts of the reply so this is on our forum for future use and should the linked site disappear.

https://www.chemicalforums.com/index.php?topic=26028.0

By Trade I'm a window Cleaner, not the type that climbs ladders as H&S is slowly putting more and more restrictions on ladder users, so now many window cleaners are changing to use the telescopic pole method where pure water is pumped up to the brush, the windows and frames are washed and left to dry naturally as you know the water contains no impurity's so doesn't dry spotty.

We produce are own pure water from tap water with reverse osmosis and deionised resin to bring the TDS reading down to 000tds, we use TDS meters to check the water.

I have just found out that we need to recalibrate our meters at least once a week with 342 ppm Na Cl solution, although this solution is available commercially at £5 per bottle, the bottle being the size of an egg cup.
I would love to make my own so this is my reason for posting on your forum.
Can any one tell me in plain English (don't forget I'm a window cleaner lol) Can I make this solution and at 342 ppm  from items easily available.

Answer

Dissolve 342 miligrams of pure NaCl in 1 liter of distilled water.

I believe kitchen salt (which is basically NaCl) is pure enough for your purposes. Just look for teh white one, not a sea salt, or microelement salt or whatever.

An additional bit of info from another poster;

Chemically pure sodium chloride is easily purchased by someone with a corporate mailing address.  It may be a little more pricey than supermarket brand table salt, but will be much purer.

The problem is the actual concentration will only be as good as the purity of your reagents -- the salt and the water to dissolve it, and your skill in careful measuring, mass of salt and volume of water.  The company selling you this high priced egg of magic juice is charging you a premium, but they guarantee their product.  Think carefully if you really want to go the DIY route. 

 

[J and S]

I have 3 meters and when used with testing fluid none of them agreed....2 were brand new and were just about the same but did not match the supposed TDS of the magic juice.