EC Meter a Waste?

After reading a lot of posts here saying that EC meters are the best way to measure PPM, I bought an EC meter from HM Digital. After going through the instructions looking for the conversion factor with no luck, I called them directly to be told that an EC meter is not an accurate way to measure PPM at all.

I must have talked to this guy for 20 minutes about this. I was talking to the gal that answered the phone but she put her boss/tech support on and he at one point said that in the industry, people get very upset about the misconception of EC meters vs. TDS meters.

He said that the only way to get an accurate PPM reading was by a TDS meter.

Has anyone else heard this? I have read a lot of people say EC is the way to go but he swears up and down that there is no accurate conversion for EC to PPM.

On my EC meter I am reading 3300 us/ms and 320 for my regular tap water. Others have said that I can half those readings for a round about PPM.

Is there an EXPERT out there that can verify or debunk this? I was floored that the guy essentially was saying that it was a big joke and pet peive of people in the know!

I wanna be in the know... Thanks

He is correct. Look at the PPM conversions for EC on the Fox Farm feeding schedule for water farms. They have two different conversions there, and they aren't close in number either. I just use a ppm meter and be done with it.

There are two different PPM conversion factors you can use with an EC meter. Check http://www.getbluelab.com/Articles/Bluelab+Measurement+Conversion+Chart.html for the conversion. Perhaps that's where the confusion lies, as what he told you was true - there is no totally accurate way to convert EC into TDS.

In the end, it doesn't matter too much - you need a qualitative measurement rather than a quantitative one. If you're growing weed you're going to need to figure out strain-specific fertigation regimes anyways - actually knowing the TDS/PPM of a solution isn't the most useful measurement. Make sense?

Edit: when I found out that Europeans tend to use the 700 conversion and most Americans use the 500 things became a lot clearer to me when it comes to online forums and articles.

Thanks you 2 for the info. I do have a TDS meter coming but for now the EC will do.

+ rep for both of you!

Thanks