Meter choice: EC vs. PPM what do you use?

[JamesFarmer]

Hey Everyone!

I have been using TDS meters that read PPM using either a .5 or .7 conversion. I didn't realize that I had meters using different conversions until it had caused me some trouble & confusion.

It still makes it too easy to make a mistake so I decided to move to meters that all read EC. I am trying to get used to the change and was surprised to see the EC meter displays a minimum resolution of .1EC which works out to 50ppm on my .5 TDS meter. That seems like a fairly "coarse" reading.

What are you all using? Those using EC meters: Is the reduced precision an issue for you??

Thanks.

FJ.

 

[zem]

I use a ppm meter DD brand http://www.warehouse-aquatics.co.uk/d-d-tds-meter.html thing with ppm is that you have to read the calibration type in the manual, mine is simply NaCl aka table salt. I made my own calibration solution 1L bottle with exactly 1 gram of salt gives 1000ppm solution. it reads concentrations very well I try it on bottled water and it's accurate doesnt go off often. it is best to calibrate your meter closer to the range which you test. calibrating with 400ppm solution and testing for 1200ppm solutions will be more off than if calibrating with 1000ppm.

 

[RB26]

Just switched my Bluelab to EC due to the same problems you came across. Not looking back anytime soon.

 

[Treetroit City]

E.C. should be standard in my opinion.

No problem with the diminished accuracy. As long as I stay between 1.0 and 1.4 from veg to flower I'm all good.

 

[rangergord]

No matter the conversion, different meters have different resolutions. Mine is .5 conversion but has a resolution of 1 ppm. I use my meter for many different purposes besides hydroponics and so EC is not the best choice for me.

 

[TheCleanGame]

Until I reach some type of 'budget' status for my medicinal growing... Whatever's cheapest.

Keep it Clean!

 

[JamesFarmer]

E.C. should be standard in my opinion.

No problem with the diminished accuracy. As long as I stay between 1.0 and 1.4 from veg to flower I'm all good.

I am going to run both side by side for a while and see how significant the difference in resolution plays out.

Thanks everyone.

 

[Mister_D]

Bluelab truncheon EC meter. Plenty accurate for the real world, and no conversion factor to be confused about. It easily reads in EC, .5 and .7 ppm. I only use EC, but the conversions are there if you need them.

 

[JamesFarmer]

I have added yet another meter to my collection. It will switch between: .5, .7, ms/cm and us/cm.

The last two being scales of EC. 1000us/cm=1ms/cm

My first "EC" meter reads 0-2 ms/cm with a .1 resolution. My new EC meter is reading 0-1999us/cm with a 1us/cm resolution. Equivelent to reading 0 to 1.999 ms/cm with a .001 ms/cm.

Root of my ramble..... Measure EC! use the us/cm scale! Uniformity & resolution!

 

[Hillbillie]

I use Bluelab.. they are super easy to use .. and last for a long time ,, for me they do.. I do clean them when done using ,, and keep calibration. Hope u find what works for you

 

[sanjuan]

I'd just point out that precision is not the same thing as accuracy.

For sharing info on the forums, I much prefer to see EC.

 

[JamesFarmer]

I'd just point out that precision is not the same thing as accuracy.

For sharing info on the forums, I much prefer to see EC.

Lack of precision = limited resolution

Precision = high resolution

Accuracy= correct and repeatable results

Awesome= Accuracy + Precision

 

[Hillbillie]

Lack of precision = limited resolution

Precision = high resolution

Accuracy= correct and repeatable results

Awesome= Accuracy + Precision

this is funny and true lol !

 

[whatthe215]

seriously we should ditch ppms, or at least choose one. even if i clarify that i'm speaking in terms of the (0.7 scale,) some people just aren't familiar with it. they don't understand the difference.

hard to screw up a 0.0-2.0 scale.

i don't think enough precision is lost for it to be a big deal.

oh yeah, Bluelab combo meter + velcro. had lotsa pens, a hanna combo and the bluelab is by far the best. the ph probe is a bit unprotected though, just gotta use the suction cup so it doesn't knock around.

i have a small strip of velcro above each of my rezs as well as my drainage/sump buckets to watch runoff while drippers run. small strip on the back of the combo makes life way easier than holding 2 pens.

 

[GreenDream]

Bluelab Truncheon is the only meter I will use (for EC/ppm)

Once I accidentally stepped on it and broke it in half. The battery side was hanging by a wire. I busted out the duct tape and it still worked! Those things are bullet proof, super fast, and precise enough for my purposes. The only time I use my old Hanna combo pen (the black HI98129) is when I need to check my R/O water and see if it is starting to run higher than 7ppm. Otherwise the Truncheon is king.

 

[Hillbillie]

I use them also Greendream .. I had same type issue ,, Broke it and it still worked.