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BlueBolts

Dean's (Ec) vs BlueBolts (TDS)

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BlueBolts

Dean's uses Ec & I use TDS to calculate the purity of our water. There's a mix of information and reference to water quality using Ec & TDS, and I appreciate many hobbyist maybe confused to which "pen" to buy, or if they've already bought a TDS pen, regret the fact as reference is made to Ec ....

Please take note of the bold words/sentences ....

Total Dissolved Solids (TDS) is the best measurement of the nutrient concentration of a hydroponic solution. To estimate TDS, one can use a meter that measures the Electric Conductivity (EC) of a solution, and convert the number to TDS in parts per million (ppm). Many meters will do this conversion.

Total dissolved solids (TDS) is typically expressed in parts per million (ppm).

Electrical Conductivity (EC) is expressed in siemens per centimeter (s/cm) or milliseimens per centimeter(ms/cm).

For convenience, EC measurements often are converted to TDS units (ppm) by the meter.

The meter cannot directly measure TDS as described above, and instead uses a linear conversion factor to calculate it.

The meter uses an approximate conversion factor, because the exact composition of the mix is not known. Conversion factors range from .50 to .72, *depending on the meter manufacturer, which approximates a TDS calculation from the meter’s measurement of EC.

* All ppm pens actually measure the value based on EC and then convert the EC value to display the ppm value, having different conversion factors between differing manufacturers is why we have this problem communicating nutrient measurements between one another.

The issue is that different ppm pen manufacturers use different conversion factors to calculate the ppm they display. All ppm (TDS, Total Dissolved Solids) pens actually measure in EC or CF and run a conversion program to display the reading in ppm's.

There are three conversion factors which various manufacturers use for displaying ppm's...

USA 1 ms/cm (EC 1.0 or CF 10) = 500 ppm

European 1 ms/cm (EC 1.0 or CF 10) = 640 ppm

Australian 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

For example,

Hanna, Milwaukee 1 ms/cm (EC 1.0 or CF 10) = 500 ppm

Eutech 1 ms/cm (EC 1.0 or CF 10) = 640 ppm

Truncheon 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

When reporting your PPM in a thread, please give the conversion factor your meter uses. For example: 550 PPM @0.7 or give the reading in EC, which should be the same meter to meter.

SUMMARY

Although TDS also measure organics etc.... all TDS pens are manufactured to calculate the Ec, and uses a mathematical formula (factor of 0.5, 0.64 or 0.7) to convert the reading to TDS. So all we need to know is the pen's conversion factor. i.e. I have two pens, the 1st calculates Ec/TDS and uses a conversion factor of 0.5 (125 ppm = 250 ms), the 2nd calculates TDS ONLY and as it's manufactured in Europe, uses a coversion of 0.64 (160 ppm = 250 ms).

In conclusion, there's no difference whatsoever if you have a TDS or Ec pen......just need to find the right conversion factor, and apply it.

:D

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torface

Great post BB!

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CNgo2006

Yet another informative post by the BB...I have often wondered about this and went and bought both pens.

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Kitz

Good write up bb! I think it's always good to have both pen so that you can cross check especially when you keeping expensive shrimp!!

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BlueBolts

Thanks, but plagerism accounts for 50% of the article ..... my logic and understanding is good, BUT "mi englis, an discliption of werds, knot vary goed. LOL

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Squiggle

Awesome write up as usual BB, I think we might have another sticky :encouragement:

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CNgo2006
Thanks' date=' but plagerism accounts for 50% of the article ..... my logic and understanding is good, BUT "mi englis, an discliption of werds, knot vary goed. LOL[/quote']

Takes you back to the days of school essays and assignments...Ah the good old days where you could copy from a book and not get busted because there was no internet back then...But then there would be no SKF so POO to that!

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Squiggle
Takes you back to the days of school essays and assignments...Ah the good old days where you could copy from a book and not get busted because there was no internet back then...But then there would be no SKF so POO to that!

+1 Agree, well said dude :victorious:

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JohnH

Thanks for the great post BB.

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ineke

It's a great post and explains it well however my pen is made in china and I don't know which type it belongs to hubby thinks its an American one made in china. It is a TDS -02 any idea which I should follow.

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BlueBolts
It's a great post and explains it well however my pen is made in china and I don't know which type it belongs to hubby thinks its an American one made in china. It is a TDS -02 any idea which I should follow.

Got a pic ? Perhaps write an email to the company that you bought it from, or compare it with someone who has a Ec pen or a person with a TDS pen who knows their conversion.... It'll either by 0.5 or 0.64.... Depends which market it is made for.

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ineke

Pretty sure it's for America the pictures don't tell much have looked it up on google only a cheap one. I'm getting an EC pen but that's a cheap one too but thought I could take a reading from each and work it back from that - or at least Alan will:encouragement:

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Dean

great write up Mr BB, and ill be the first to admit i DID NOT KNOW THAT :)

glad it is all clear and easy to understand now for everyone.

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hoang1912

NOw I am understand what is EC and how's it work :)). Thanks BB.

BUt how can we find right conversion factor?

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BlueBolts

Check with the seller, or determine which market the pen is made for, or compare it with a Ec pen......

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hoang1912

There is no word on my pen. Only TDS, on/off and hold ;)). BUt I will ask the seller. This is a good article for a newb like me :victorious:

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Gbang

Bb you sooooosmaaaaaart!!! Thanks for the write up :)

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shrimpstan

u answered all my questions before i even asked. seek and u will find... at SKF!! :)

good on ya BB!!

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Foxpuppet

Dean's (Ec) vs BlueBolts (TDS)

I'm using this pen, anyone know the conversion factor it would use?

post-1452-139909851333_thumb.jpg

It says 100 in the small writing on the LCD and 06 as the reading.

post-23-139909850151_thumb.jpg

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JohnH

600 EC is a little high if that's what it is reading. What's in your tank?

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Squiggle

Wow 600 is a little high, around 200-300 is probably a bit better, depending on the shrimp you're keeping :encouragement:

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Foxpuppet
600 EC is a little high if that's what it is reading. What's in your tank?

I'm thinking the calibration is off somehow. Ill check some ro water this afternoon and compare. What should straight ro read?

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durro68

Should be close to 0. Depends on if you need to replace some of the R/O unit bits.

I just tested the water I use TDS 2 and EC 5 micro siemens

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Foxpuppet

my Gh has been around 8-9 it's slowly crept up over the last few months, so in response to that i have been taking out 2 litres (from a 200ish litre tank) every few days and Drip replacing with RO. just checked EC and it's now at 5. i used to have a TDS pen but it went on the fritz so this pen was what i replaced it with.

the RO water tested at EC 0

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blackcat

What a brilliant post thank you so much :kudos:

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