What to look for in an EC meter?

beth11

15 years ago

Hi All,

I'm new to hydroponics and would like to purchase an EC meter. What features should I look for??

Thanks,

Beth

Featured Answer

freemangreens

15 years ago

I read your article; very informative.

I would like to point out, however, that all most growers need is a "benchmark". By that, I mean something akin to a "home plate", a starting point that remains in the same place (constant).

I use a Bluelab Truncheon. It has little red blinking lights (LED's) and it gives me a "base-line" from which to maintain some consistency in my nutrient solution. It's a no-brainer to use; very simple, rugged and accurate tool!

I brew my own nutrient and the water I use is loaded with calcium; having an EC of 1.2 right out of the tap. If I didn't have a way to measure that, I'd miss my proper EC range by a mile, so for me (and most others) a consistent tool is a necessity. Granted, the Bluelab Truncheon is the "Gold Standard" in our industry and even though it was a little pricey, I have no regrets. It's trustworthy (I know, because I test it against a "known" every now and then).

Your comment regarding EC and pH is a very important point. Depending on what one uses as a pH up or pH down, the conductivity can become somewhat of a joke.

My nutrient is self-buffering, so I adjust its pH in a totally different manner (Lewis-Bronsted Acid-Base Theory) than the rest of the crew here on the forum. Still, I always test EC before, during and after brewing a batch of nutrient. It's THAT important, to be sure!

I have found out (the hard way!) that growing stuff outside the accepted standard EC or pH range can be disastrous. I post links to EC and pH range charts on my Web page. There really is something this "EC" business.

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Comments (12)

grizzman
15 years ago
Whatever you do; don't shop for price.
That being said, buy the truncheon EC meter. it's pretty much the gold standard.
I've heard tell you can get them for around $40 on Ebay. I bought mine new for $100 about 5 years ago.
Pros:
No calibration
runs on AA batteries
waterproof
provides EC, microsemens, and two ppm scales. (stick with EC readings)
doubles as a stir stick.
freemangreens
15 years ago
Mega-dittos on the Bluelab Truncheon.

If you were to buy only one tool ever, make it a Truncheon. You can skimp on lots of things, but you MUST know what your EC is to grow things properly using hydroponics.

Here is a link that might be useful: Here's Bluelab's link
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beth11
Original Author
15 years ago
Hi All,

Thanks. Do you have any thoughts on Extech meters?

Thanks,
Beth
hydroponica
15 years ago
I don't have any experience with the Extech, but I know for sure that the Bluelab is fantastic. You never need to calibrate it.

Tough as nails, works every time. Can't beat that.

Though if the rumors from Advanced Nutrients are to be believed you might not even need any meters before long.
danielfp
15 years ago
Well, EC meters belong to the past. EC measurements have a lot of problems and are often over exploited. What about using selective ion electrodes to measure your actual levels of K, N and P ? This can actually be done ! and it is not as expensive as you would think. I wrote an article on EC in hydroponics if you would like to check it out . http://allhydroponics.blogspot.com/2009/02/faq-electrical-conductivity-ec-in.html

Here is a link that might be useful: Everything about Hydroponics
hydroponica
15 years ago
You said pretty much everything I would've said, and a bit better really.

Like freemangreens says, it's not necessary for most hobby growers to know precise ppm or EC or anything else. What's important is that whatever the number is on one day reads exactly the same way on the same meter the next day. The accuracy of the meter is what's important, not the units of measure. Whether it tells you what your ppm is, your EC, or some kind of weird "saltiness scale" it doesn't matter as long as it always reads the same amount for the same solution.

That's why the Bluelab Truncheon is such a gem. The only thing you have to do to it is change the batteries one in awhile and rinse it off after each use. That's it. And it stays calibrated for years.

As long as you know where the lights on the stick need to be for your plants, it isn't important to know what the units are.
hydro-grower
15 years ago
Do you guy's use the same brand to test your PH??
grizzman
15 years ago
None of us are sold on any one brand of pH meter. I use a Hanna because it was cheap when I bought it ($18) and it has held up. Others simply use litmus paper from the fish tank supplier. I'm sure there are others who use the truncheon.
danielfp
15 years ago
You can try to use chlorophenol red to test the pH of your nutrient solution. It is a cheap efficient way to do so. I wrote an article on my webpage about this yesterday, you can check it out here (http://allhydroponics.blogspot.com/2009/02/checking-ph-of-your-hydroponic-system.html). I hope it helps those who can't purchase a pH meter !

Here is a link that might be useful: Everything Hydroponics
grizzman
15 years ago
The only problem I see with the chlorophenol is often times your initial solution is not clear. I know mine is blue, so the color scale would be off. the use of chelated iron would make it red I believe.
hydroponica
15 years ago
There isn't any pH meter that stands as decisively ahead as the truncheon does among EC/ppm meters.

I was going to get a pH meter, and I might still someday, but after looking into the initial outlay of money, plus the calibrating solutions you need to use pretty regularly, and of course the actual task of calibrating them frequently... it just seems like an awful lot of work to go to for me. I have test strips that read 5.5 to 8.0 that work well enough for my needs.

There's a bit of peering at the strip and the key and trying to decide if it's more one color or the other, but plants are pretty adaptable so it's not brain surgery. Pretty close is fine.

Though if the new stuff Advanced Nutrients is supposed to be unveiling does what they say it does, I might not even need the test strips. Their stuff is supposed to go past buffering and actually reactively adjust it's own pH in addition to the industry standard buffering.

Looks interesting. I'm gonna see if I can score some to review it for my blog.