# Meter only reads us/cm and I need ec, can I convert?



## spannerhead (Apr 11, 2014)

I bought an ec meter from eBay and it only reads us/cm. Can I convert this to ec or is it just a cheap shit meter and I need to get a decent one? Googled it but can't find a conversion chart.


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## DroidBoy (Apr 11, 2014)

The chart i use only does ec ,cf and the normal ppm conversions, im sure some 1 n here could convert for u tho


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## Spanky84 (Apr 11, 2014)

EC is measured in Siemens per meter. (S/m). Convinient unit is microseimens per centimeter (uS/cm) or milisiemens per centimeter (mS/cm). What is often refered as EC is actually mS/cm, so if you want that measurement you just divide uS unit with 1000.

TDS (ppm) is actually not a very good measurement unit as it is the estimate (wrong estimate) of the amount of diluted solids. There are three different conversion charts from EC to TDS, so you can expect much confusion when using it.

USA 1 ms/cm (EC 1.0) = 500 ppm
European 1 ms/cm (EC 1.0) = 640 ppm
Australian 1 ms/cm (EC 1.0) = 700 ppm


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## Sativied (Apr 11, 2014)

Only difference between most EC and most ppm meters is that the ppm meter converts the value to ppm for the display. Check out the following reference:
http://milwaukeetesters.com/pdf/ph-ec_info.pdf

If it's a 0.5 factor, which most of those cheap chinese clones on ebay use, it's just a matter of doubling the value and removing 3 zeros. E.g 500 ppm = 1.0EC


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## waterdawg (Apr 12, 2014)

Spanky84 said:


> EC is measured in Siemens per meter. (S/m). Convinient unit is microseimens per centimeter (uS/cm) or milisiemens per centimeter (mS/cm). What is often refered as EC is actually mS/cm, so if you want that measurement you just divide uS unit with 1000.
> 
> TDS (ppm) is actually not a very good measurement unit as it is the estimate (wrong estimate) of the amount of diluted solids. There are three different conversion charts from EC to TDS, so you can expect much confusion when using it.
> 
> ...


It is my understanding that all meters, EC and TDS meters measure EC, the difference being TDS meters do the calculation re. Multiplication factor for you. Knowing the conversion factor will enable you to know both. My HM EC-3 has a conversion factor of .5 so if my display shows 1000 my tds is 500. Not sure why EC is better or worse, are they not the same thing really. But yes it can be confusing to say the least lol.


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## waterdawg (Apr 12, 2014)

Basically i copied what Sativied said, sorry dude!!! So yes what he said lol.


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## Sativied (Apr 12, 2014)

waterdawg said:


> Not sure why EC is better or worse, are they not the same thing really.


Technically EC is more accurate because the conversion factors used are simplified, there's another factor that plays a role. Don't remember what it was, similar to temperature in ph measurement. However, most cheap meter are not THAT accurate in the first place, so the rounded result on the screen is the same.

Being in europe I was used to EC but now buy ppm meter on purpose. Just a personal preference, numbers like 400-1000 ppm work better than 0,8-2,0 etc.


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## waterdawg (Apr 12, 2014)

I do t actually pay much attention to the readings to be honest. I use it to monitor fluctuations and as a reference point re: amount of nutes to get to same point every refill. Yes its a cheap one lol.


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