# TDS meter or not?



## dwalsh1 (Mar 3, 2010)

I have an XL Everpure Claris cartridge attached to my machine since June 2012 and I'm getting paranoid that I need to change it but could be wasting my money because there could still be months left on the cartridge. How can I tell whether it needs changing or not? is it a case of simply attaching a TDS meter to the incoming/outgoing water to test for hardness? I have this in mind http://www.ebay.co.uk/itm/HM-Digital-In-Line-Dual-TDS-Meter-Genuine-not-Fake-/221243993866?pt=UK_Pet_Supplies_Fish&var=&hash=item33832b6f0a


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## repeat (Nov 14, 2009)

I test for hardness and ph using fish tank test kits. Work great and cheap. Pretty sure the brita equiv cartridges should be changed every 12 months regardless. No idea why other than its in the documentation. Only reason I could guess at would be bacterial build up (for example my filter also feeds a cold tap on the sink so is never boiled).


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## Glenn (Jun 14, 2008)

I can drop around my refractometer if you like. Very easy to measure water hardness - takes seconds


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## dwalsh1 (Mar 3, 2010)

Sounds good to me Glenn. Thanks.



Glenn said:


> I can drop around my refractometer if you like. Very easy to measure water hardness - takes seconds


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## PaulN (Mar 10, 2011)

Ive got a TDS meter for my resin vessel which pumps out 0ppm water.

This should help http://www.cleaningspot.co.uk/acatalog/TDS_meters.html

I would say very few domestic filters are designed or really should be giving you 0ppm water not sure if its any good for drinking? But for me i use it when washer cars...


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## dwalsh1 (Mar 3, 2010)

Thanks for the replies. Have ordered a HM TDS 3 meter so I can check at regular intervals.


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## sjenner (Nov 8, 2012)

I use this TDS meter to check the amount of harness that my remineralisation (calcite bed) filter is achieving following reverse osmosis filtering... So the input reads something less than 5ppm, and the output reads somewhere between 55 and 95 ppm of "total dissolved solids", which will be only calcium and magnesium, since that is all that is in the calcite bed.

In my experience, and this is in London where total hardness regularly measures approaching 400ppm, that the Everpure is not that effective. I used one for a while with my Londinium, but my tests even at the lowest "blending level" were delivering water with unacceptably high levels of hardness.

The best kit for testing for "total hardness" is this:

http://www.hach.com/total-hardness-test-kit-model-5-b/product?id=7640219508&callback=bc

Reiss at Londinium also does one, but his site is currently transitioning... When it is up and running, I might go into my water experiments a little more fully, since Reiss and I worked together on much of it.


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## dwalsh1 (Mar 3, 2010)

sjenner said:


> Everpure is not that effective.
> 
> Reiss at Londinium also does one, but his site is currently transitioning... When it is up and running, I might go into my water experiments a little more fully, since Reiss and I worked together on much of it.


 Funny you mention that. it was Reiss who convinced me that Everpure was the best thing since sliced bread.


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## dwalsh1 (Mar 3, 2010)

Just done a test of my tap water using my new toy and the reading was 404 ppm and the water from the group of my machine read 296 ppm. Not sure if I need a new cartridge or not


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## ronsil (Mar 8, 2012)

Out of interest the Manchester water from the tap in my house hovers between 60/70 ppm.

Although very soft I still protect my La Spaziale with a Bestmax filter in line. I change the cartridge annually at Christmas.


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## repeat (Nov 14, 2009)

dwalsh1 said:


> Just done a test of my tap water using my new toy and the reading was 404 ppm and the water from the group of my machine read 296 ppm. Not sure if I need a new cartridge or not


I would say you do. From my speedster manual:

"As a rule of thumb, the amount of total dissolved solids (TDS) in your water should be 100-150 mg/l (=ppm)."


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## painty (Jul 25, 2011)

dwalsh1 said:


> Just done a test of my tap water using my new toy and the reading was 404 ppm and the water from the group of my machine read 296 ppm. Not sure if I need a new cartridge or not


Be interested to hear how much lower it is with the new one. This water hardness malarkey is like witchcraft!


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## dwalsh1 (Mar 3, 2010)

Surely that 100-150 ppm marker would depend on the hardness of water in your area? I've got rocks coming out of my tap here. I'll be installing a new Brita C150 in a couple of days.



repeat said:


> I would say you do. From my speedster manual:
> 
> "As a rule of thumb, the amount of total dissolved solids (TDS) in your water should be 100-150 mg/l (=ppm)."


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## repeat (Nov 14, 2009)

Hence why I have a filter. When the filters effectiveness reduces I need to change it. Did you test the hardness when you first installed your Claris?

I would look at the brita doc before I bought the c150 as depending on the %bypass you select determines the litres you get out of the filter. I'm in a hard water area and use the c300 with the bypass set at 20 to get the best compromise on hardness and acidity (the more lime scale you take out causes ph to become more acidic) with the hope it would last 12 months. Actually lasted 10.


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## repeat (Nov 14, 2009)

From what you are telling me the filter is removing hardness but I have no idea how effective it's being. Have you a way of measuring the hardness rather than the tds?Never used a tds meter so no idea what readings you can get.


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## dwalsh1 (Mar 3, 2010)

I thought measuring the tds is a way of measuring the hardness but I'm naïve to all this tds malarkey so need a little guidance. I didn't mind descaling the Duetto when I had it because it had a tank but owning a commercial machine is worrying me with scale build up. Hopefully coffeechap is bringing a new cartridge with him tomorrow when he visits my house so I will take readings then.


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## sjenner (Nov 8, 2012)

ronsil said:


> Out of interest the Manchester water from the tap in my house hovers between 60/70 ppm.
> 
> Although very soft I still protect my La Spaziale with a Bestmax filter in line. I change the cartridge annually at Christmas.


It would be interesting to know what the PH of your water is Ron...?

My RO + calcite bed hatchet job on disgusting London water is getting close to the SCAA recommended measurements, however at around PH8-9 it is quite alkaline.

The upshot is that my L1 shouldn't need rebuilding for a very long time.

Apart from the fact that the place is full of Tories at the moment, Manchester sounds quite a good spot for making good coffee without too much messing about, I am not sure whether you really need a filter.


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## repeat (Nov 14, 2009)

From my understanding tds is all dissolved solids in water. Organic, inorganic, etc. the figure I gave for tds is where the best tasting water is apparently.

Hardness is a measure of how much calcium and magnesium carbonate are in the water. This (limescale) is the bigger problem as it has limited solubility and therefore comes out of solution easier during boiling and cooling. I would think it's the main component of tds. I use a kit that tells me specifically the water hardness in German degrees. Before filter around 20 which is hard. After filter, 3-4 which is the upper recommendation from kvdw. I can send you my test kit (ph, hardness) in the post if you pm me your address.


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## dwalsh1 (Mar 3, 2010)

Cheers mate. PM sent.


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## ronsil (Mar 8, 2012)

sjenner said:


> It would be interesting to know what the PH of your water is Ron...?I am not sure whether you really need a filter.


its called piece of mind!.

Am away at the moment but when I get back will test the PH again & post result.


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## painty (Jul 25, 2011)

sjenner said:


> Apart from the fact that the place is full of Tories at the moment, Manchester sounds quite a good spot for making good coffee without too much messing about, I am not sure whether you really need a filter.


Yes 60-70 ppm is a great compromise figure for running through a machine. Maybe just a carbon block taste and odour filter to take out the organics. I'm definitely moving to Manchester once the tories have gone...


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## sjenner (Nov 8, 2012)

painty said:


> Yes 60-70 ppm is a great compromise figure for running through a machine. Maybe just a carbon block taste and odour filter to take out the organics. I'm definitely moving to Manchester once the tories have gone...


Yes painty, good point, in the excitement I forgot about chlorine etc..


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## mike.khan.140 (Oct 26, 2013)

TDS is a measure of 'Total Dissolved Solids' so that's everything dissolved in your water. The limescale element of this is typically the biggest proportion but there is other stuff in there too.

Most 'taste & odour' filters will have an activated carbon element, which will Hoover up free chlorine. Good news! As chlorine doesn't improve the taste of your coffee. However, removing the chlorine makes your water susceptible to bacteria and algae growth, so best to have your filter as close to your machine as possible.

Removing the limescale is a little more complex. Most treatment systems use an ion exchange resin, this is a load of tiny spheres which have sodium ions stuck to them, as the calcium rich water passes through, the resin takes up the calcium and gives away an equal amount of sodium. If you are using this system, measuring the TDS will not tell you anything about the amount of calcium hardness (limescale) in the water, as the TDS will remain the same. You will need to measure using test strips or solution for hardness. For best taste, coffee needs total hardness of around 150 to 180 ppm with the temporary hardness making up around 125 - 150 ppm. As luck would have it, this is also not a bad water quality for your machine. Some light scale will form, but just enough to create an extra barrier between the metal surfaces and your universal solvent (water). Water with very little hardness will make poor coffee and could have high alkalinity, this will result in premature corrosion to any metal parts of your coffee machine.

Some filters use a system of adding a chemical to the water (poly-phosphates) this sequesters the calcium, that is to say it bonds to the calcium in solution in the water. This prevents the calcium forming concrete deposits, allowing it to flow through the machine without forming excessive scale. Again, measuring the TDS or even the hardness will not tell you that this system is in place, so you will not know what to expect to find in your coffee or your coffee machine.

The very best solution for getting the right water treatment for coffee is to test the water to understand exactly what's in it, and work with a water filter specialist who can recommend a solution to best meet your needs. Sadly, there are many water filter distributors who will tell you their single solution is all you need. Patently this is not true. Ask lots of questions!


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## PeterL (Aug 5, 2015)

Reviving a very interesting thread................

What have people moved onto in terms of testing water hardness these days? I have a filter of unknown duration working on unknown hardness and I would like to move to something a little more structured.


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## DavecUK (Aug 6, 2013)

PeterL said:


> Reviving a very interesting thread................
> 
> What have people moved onto in terms of testing water hardness these days? I have a filter of unknown duration working on unknown hardness and I would like to move to something a little more structured.


Just buy a TDS meter, for all practical purposes it will give a direct reading of water hardness....£15 and your sorted.


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## espressotechno (Apr 11, 2011)

Ouch ! 3 years + on a water softener cartridge ! London water is as hard as rocks.

Fit a new one asap - is it worth risking your £1000 machine scaling up for say £60 ?


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## dwalsh1 (Mar 3, 2010)

I used to use a Brita C150 but now for peace of mind I attached a C300 for a year. Better safe than sorry.


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## DavecUK (Aug 6, 2013)

dwalsh1 said:


> I used to use a Brita C150 but now for peace of mind I attached a C300 for a year. Better safe than sorry.


Ohh, just read the filter bit, if it's Ion exchange, then a TDS meter won't help you as calcium is exchanged for sodium and both register almost the same TDS value.....but one scales, the other doesn't.


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## PeterL (Aug 5, 2015)

DavecUK said:


> Just buy a TDS meter, for all practical purposes it will give a direct reading of water hardness....£15 and your sorted.


So stupid time question, TDs is all mineral solids, I thought from above that you are swapping calcium for another mineral such that the level would be the same?


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## DavecUK (Aug 6, 2013)

PeterL said:


> So stupid time question, TDs is all mineral solids, I thought from above that you are swapping calcium for another mineral such that the level would be the same?


Yeah see my post above


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## mrsimba (Mar 17, 2014)

Tested my newly installed 3M Scaleguard filter tonight with the Londinium TH Water Test Kit. The Scaleguard is designed for removal of hard water scale and chlorine specifically for coffee machines, so retains the PH of the water .

Very impressed, my local water is known to be very hard & that turned blue at 10 drops, it started to turn at 9 drops and 10 straight to blue.

The filtered water did not go to the deep pink of the 'tap' water and at 3 drops started to turn at 4 was pale blue and deeper at 5

So the 3M has dropped the hardness of my water from 170 to around 75 so pleased with that









I had bough one of the electric TDS meters from eBay... it measured the same samples of water at 245 / 240 so that was a complete waste of time for trying to test how well the filter was working!

& having just read this above it now makes sense! - So I'd conclude whilst you can test the hardness of water straight from the supply with a TDS meter you can't rely on it to test if your filtration is still good or not!



> Removing the limescale is a little more complex. Most treatment systems use an ion exchange resin, this is a load of tiny spheres which have sodium ions stuck to them, as the calcium rich water passes through, the resin takes up the calcium and gives away an equal amount of sodium. If you are using this system, measuring the TDS will not tell you anything about the amount of calcium hardness (limescale) in the water, as the TDS will remain the same. You will need to measure using test strips or solution for hardness.


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## Xpenno (Nov 12, 2012)

mrsimba said:


> Tested my newly installed 3M Scaleguard filter tonight with the Londinium TH Water Test Kit. The Scaleguard is designed for removal of hard water scale and chlorine specifically for coffee machines, so retains the PH of the water .
> 
> Very impressed, my local water is known to be very hard & that turned blue at 10 drops, it started to turn at 9 drops and 10 straight to blue.
> 
> ...


Nice work









Not sure who told you to measure hardness with a tds meter though. As you have found TDS and Hardness are two different measurements and there is no conversion and barely any correlation between the two! Now go enjoy some tasty coffee with that lovely water.


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## mrsimba (Mar 17, 2014)

Xpenno said:


> Nice work
> 
> 
> 
> ...


It was my mistake - a friend uses RO and he checks his water with a TDS meter, but my mistake was not calculating that he removes everything with the RO back to '0' and then rebuilds using the TDS as a 'guide', trying to measure unfiltered 'mains' water vs filtered 'mains' water the same way does not work!

Reading some more just read that corrosion of the boiler is a risk below 50 & above 85 its scale build up time so in the 70's from a filter is good with me as I just wanted to get the L1 up and running, though at some point (probably after I've finshed reading Maxwell's book!) I'll have a look at RO systems & see if any are small enough for my kitchen cupboard!!! they are certainly getting cheaper and more cost effective!

The Scaleguard is a bloody big thing though at nearly 2 foot long!


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## risky (May 11, 2015)

mrsimba said:


> just read that corrosion of the boiler is a risk below 50


Why is this?


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## Xpenno (Nov 12, 2012)

risky said:


> Why is this?


Water is a solvent and the lower the tds the stronger a solvent it is.


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## risky (May 11, 2015)

Xpenno said:


> Water is a solvent and the lower the tds the stronger a solvent it is.


And this is presumably the argument used for why you shouldn't drink RO water?


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## Xpenno (Nov 12, 2012)

risky said:


> And this is presumably the argument used for why you shouldn't drink RO water?


Yeah, no idea if it does affect the body in the same way but people argue that it actually leeches minerals out of your body. Some argue that it's good for you as it's so pure. I've seen no evidence either way. My best guess is that you body can't actually do much with pure h2o and the reason it is good for you is for the minerals dissolved within it.


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## risky (May 11, 2015)

It's GCSE biology and chemistry all over again


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## Xpenno (Nov 12, 2012)

risky said:


> It's GCSE biology and chemistry all over again


Without any facts to back it up


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