Could one use an ohmmeter (in a multimeter) instead of an EC meter?

[SoEx]

Is EC simply conductivity measured in Siemens?

Siemens are supposedly the inverse of resistance (in ohms).

e.g. 333.33 ohms == 1/333 siemens or .003 siemens or 3 milliSemens. Supposedly corresponding with 1500 ppm ( http://www.hydroponics.net/learn/debate_over_ec_and_tds.asp )

So what's so special about EC meters? Does the probe have to be precisely designed? For what spacing is this standardized over (probe spacing?).

Anyone have any clues? It'd be sweet if I could hook up a probe to my multimeter and get a value for resistance, convert to conductivity so I could know my EC rather than guessing or having to buy a meter.

If I do end up having to buy a meter, I'm trying to find one (as well as a ph meter) on the very cheap, so I'll probably look secondhand on ebay or something.

Edit: perhaps it's siemens/cm or siemens/m?

 

[boroboro]

It sounds plausible, although it does depend on the probe separation (i.e. millisiemens/cm is the unit used, isn't it?).

I've tried, though, and didn't really get a good reading. I wasn't using the best ohmmeter in the world, but it was a decent Fluke multimeter (about $100 unit).

 

[SoEx]

It sounds plausible, although it does depend on the probe separation (i.e. millisiemens/cm is the unit used, isn't it?).

I've tried, though, and didn't really get a good reading. I wasn't using the best ohmmeter in the world, but it was a decent Fluke multimeter (about $100 unit).

Ah, glad at least I wasn't the first to think of it.

I suppose I'll try it out, but I may not get very good results either. I have an old fluke multimeter, no benchtop ohmmeter at the moment. I do wonder, though, a nice bench ohmmeter that is precise to a few decimal places might work. But then again, I can probably find conductivity meters for cheaper at that point

Edit: I don't know if it's mS/cm or not, I'm new to this whole hydroponics business

 

[shishkaboy]

Just had this same idea and searched multimeter.

Now I know its theoretically sound but I was thinking of taking a different approach using ohms law.