HM tds pen

[Shrimp Aqua]

Gday Guys, hope this does not sound like a dumb question, i bought a HM pen model ap2 & i think it measures in EC. I cant find any conversion NO' to convert to PPM can any of you help, it does say in the op sheet calibrated to 700us; adjustable. So is this the conversion number to use. My water reading says 194 is this OK.

Talk about confused, never had a TDS pen before, HELP PLEASE!!!!!!!!!!!!!!!!!!

[Squiggle]

Can you post up a pic of it?

[BlueBolts]

Pretty sure the HM Aquapro is a Ec reader. The different TDS conversion is based on Ec, and depending on the comparison or reference used (i.e. if referring to Salty Shrimp (Europe)), then the conversation to TDS is 0.64, which is a TDS of 124ppm. Salty shrimp recommends a Ec of 200, +/- 50.

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

TDS does get confusing due to the difference convertions used.

[jayc]

Gday Guys' date=' hope this does not sound like a dumb question, i bought a HM pen model ap2 & i think it measures in EC. I cant find any conversion NO' to convert to PPM can any of you help, it does say in the op sheet calibrated to 700us; adjustable. So is this the conversion number to use. My water reading says 194 is this OK.

Talk about confused, never had a TDS pen before, HELP PLEASE!!!!!!!!!!!!!!!!!![/quote']

You have an Aquapro AP-2, that is an EC pen, not a TDS pen. As such there is no conversion rate to tds.

If you wanted a TDS pen, you need the AP-1.

[Shrimp Aqua]

• 
  
• IN-LINE MONITORS
  
• CONTROLLERS
  
• ACCESSORIES
  [h=1]AP-2: AquaPro Water Quality Tester (EC)[/h] Keep the AquaPro on your fridge. It's magnetic!
  
  
  
  
  HM Digital introduces its new AquaPro series, a line of handheld TDS/EC meters with a sleek design that's perfect for today's modern kitchen. The AquaPro digital water testers are the next generation for today's tech-savvy and health-conscience consumer.
  [h=2]FEATURES[/h]
  
  • Measures electrical conductivity (EC) and temperature.
    
  • Automatic Temperature Compensation (ATC)
    
  • Water-resistant housing
    
  • Measurement Range: 0-9999 µS
    
  • Digital Calibration (push button)
    
  • Auto-off function, data-hold function and low-battery indicator.
    
  • Display: large and easy-to-read LCD screen includes simultaneous temperature reading.
    
  • Factory Calibrated: The AquaPro is calibrated with a 700 µS solution. The meter can be recalibrated with digital calibration using the push buttons, rather than a screwdriver.
    
  • Includes a cap and batteries.
    
  • Includes a storage case.
    
  • Magnetic body (patent pending)
    
  • Need help deciding which meter is right for you? View our TDS/EC Meter Selection Guide.
    
    [h=2]SPECIFICATIONS[/h]
  EC Range: 0-9999 µS (µS/cm)
  Temperature Range: 0-80 °C; 32-176 °F
  Resolution: 1 µS; Temp. resolution is 0.1 °C/F
  Accuracy: +/- 2%
  Calibration: Digital calibration by push button.
  Housing: Water-resistant
  Power source: 1 x 3V button cell (included) (model CR2032)
  Dimensions: 15 x 2.8 x 1.3 cm (5.9 x 1.1 x .5 inches)
  Weight: 42.5 g (1.5 oz)
  
  [TABLE]
  
  [TD=class: xl65, width: 153]UPC: 891144000137[/TD]
  
  [/TABLE]
  U.S. PATENT D602,384S
  
  To convert µS (micro-Siemens) to mS (milli-Siemens): divide by 1000.
  1000 µS = 1 mS
  EC = Electrical Conductivity
  
  >> Looking for a TDS meter? If you are looking to measure TDS (in PPM), we recommend not purchasing an EC meter. Instead, we suggest one of these TDS meters:
  TDS-3
  AP-1
  
  
  
  Here we go this is what i have.

[Shrimp Aqua]

BB i read your thread where you did the comparison with Dean on the differing method of measuring EC and TDS, so if the reading i got from this model pen was 194 is this as EC?

[Shrimp Aqua]

Squiggle i hope this photo and description helps.

[Squiggle]

Yeah it's definitely an EC pen, good thing is, as BB mentioned, SaltyShrimp specs are in EC so you won't have to do a conversion to get your mineral levels right. :encouragement:

[Shrimp Aqua]

Hey Squiggle, so the reading i got of 194 is really 194EC and recommended EC for CRS is 200+/-50, is this correct?

[Squiggle]

That is correct. :encouragement:

[Shrimp Aqua]

Thanks Squiggle, BlueBolts & jayc much appreciated, sure can be confusing to an amateur.

[jayc]

No problem.

I have the HM AP-1, which is the TDS meter.

HM suggests that if you want to measure TDS, get a TDS pen. BUT, if you really have to convert your EC reading to TDS, you can use NaCL as a reference, which is 0.5. So your EC of 194 = 194 * 0.5 = 97 TDS (approx).

That's a bit low for CRS.

You'd want to try for TDS of 150 (+/-10) or EC or 300 (+/- 20) for CRS/CBS.

[BlueBolts]

TDS is a conversation of Ec. Salty Shrimps recommends Ec @ 200, so if you're using US conversion (0.5) the TDS is 100, vs European conversion (0.64) the TDS is 128…when reading thread/www, and there's a reference to TDS, we need to know what the conversion factor is. If there's a reference to say TDS 150, a person using a 0.5 conversion pen will assume the Ec is 300, vs a person using a 0.64 conversion pen will assume the Ec is 234.

[jayc]

HM digital says if you use NaCL as a reference it's 0.5.

So which one would use use if you had to convert EC to TDS? 0.5 or 0.64?

[BlueBolts]

HM / NaCl, I presume is for the US market/reference base. But if we're using a European product/reference like salty shrimp, we will then need to convert it back to the US reference if the TDS pen is US converted. Unsure of the history of the varying conversion around the world, but TDS in the US is different to TDS in Europe, but Ec is the same.

One of my Ec/TDS pens allows these different conversion rates.....so I can adjust the rate to be 0.5, 0.64...etc.