# Tap water PPM?



## GTL_UK (30 Dec 2014)

Hi.  Just bought ppm meter and I can believe what im seeing.... 
Fish tank 220ppm
Tap water 30ppm...  Is that possible?  I'm in north west


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## darren636 (30 Dec 2014)

Leave the tap water to warm up.
Are you calibrated  to near 300 ppm?

Some test pens are calibrated at 1331 ppm.
Which is pretty rubbish for use at our lower levels.


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## Jose (30 Dec 2014)

I believe it might be possible for the soft waters of the north and Wales. Although 30 is like RO water. Yeah you might want to calibrate your pen.


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## Andy Thurston (30 Dec 2014)

Definitely possible low TDS tap water in certain areas of the uk
My tap is between 60-70 ppm and I've read a few posts recently where members TDS is around 45ppmm from the tap.
My tank is around 150 after weekly water change and between 200-220 just before


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## X3NiTH (30 Dec 2014)

Entirely normal.

Generally Tank water TDS is higher because of all the biological processes in the tank that add to it. The tap TDS is low but not zero, you won't ever get zero out the tap because the pH will eat copper pipe, buffers are added to bring the pH above 7, this adds TDS, chlorine may be added and chloramine also to make the water safe to drink, this will also add TDS, mineral content (measured as GH and KH) are likely low but will constitute some part of the TDS. 

My tap TDS is 30-40, municipal supply fed by reservoir caught rainwater coming of the hills.


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## GTL_UK (30 Dec 2014)

The meter is brand new so should I calibrate it anyway?


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## Andy Thurston (30 Dec 2014)

It should come with a calibration certificate what ppm it was calibrated to. It should be calibrated with the ppm that is closest to the range you are measuring


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## X3NiTH (30 Dec 2014)

More than likely its factory calibrated and there is no need. 

You have a baseline already in that your tap TDS is 30 (you can compare this figure with your local water authority report to see if it's in the right ballpark) and tank at 220, so as expected it has measured a difference between the samples, the tap TDS is unlikely to ever be much lower than 30 so you know it's not giving you a wildly inaccurate higher value.


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## GTL_UK (30 Dec 2014)

No certificate...  It was £3 new☺


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## GTL_UK (30 Dec 2014)

So what calibration liquid do i need ? with 0 ppm ?


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## Andy Thurston (30 Dec 2014)

This one
http://m.ebay.co.uk/itm/181537013631?nav=SEARCH


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## darren636 (30 Dec 2014)

Gah!

I couldn't find one that low !


Had to settle for  240 ppm


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## GTL_UK (30 Dec 2014)

So with liquid from your link do I calibrate it to 0 or 90?


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## Andy Thurston (30 Dec 2014)

darren636 said:


> Gah!
> 
> I couldn't find one that low !
> 
> ...


That was the only one i could find. 
I wonder if its possible to use de ionised water with 0ppm or if you would need at least some ppm to calibrate accurately


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## Andy Thurston (30 Dec 2014)

GTL_UK said:


> So with liquid from your link do I calibrate it to 0 or 90?


90


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## darren636 (30 Dec 2014)

GTL_UK said:


> So with liquid from your link do I calibrate it to 0 or 90?



 Get your tds calibration solution.
Pour enough into a cup to dip your pen in.  Turn on pen . Leave pen in solution for 5 minutes and calibrate ( with a small screwdriver)  the LCD display to read  the correct value. 
In your case 90 ppm.
Or whatever ppm your calibration solution is.


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