New2It said:

Sorry, not sure where to post this, but looking for thoughts on PPM meters. I got a vivosun one to begin, then just got another one for shits and giggles... I'm kind of weird about things not giving me accurate readings. So, in my tap water they read within 5-10 of each other, in distilled water they're dead on, then in my runoff they are WAY different.... that concerns me. What should I do? which one do I trust? Please and thank youView attachment 2467191

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neneboob said:

It sounds like you need to calibrate them.

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Grownsince95 said:

Is the one reading higher in the runoff also reading higher in the tap water and vice versa? Or is it random?

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ArtfulCodger said:

Any chance one is set to read PPM700 and the other is PPM500? That could account for it.

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ArtfulCodger said:

Any chance one is set to read PPM700 and the other is PPM500? That could account for it.

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Grownsince95 said:

There's your answer. The math even checks out. The higher reading is for ppm/700.

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New2It said:

How and why would there be different settings or whatever? Isn't it a straightforward sort of thing? So quite possibly I've been doing this wrong the whole time? This begins to suck dude. I just want stuff that works properly

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JIMKSI64 said:

The Vivosun box set and my lack of identifying PH related issues killed my first 2 plants.

EC/ppm tools need calibration. The fluid needed is NOT standardized. You will need to research your tool to see what you need. 2 different tools may need different solutions.

Also FYI. Not optional. Calibrate your tools for pH and EC/ppm. Write down everything. I can not stress this enough about writing down trends in your grow.
A lot of guys get into a rut where they pour the same nutes in the same amount of water and for 6 nute mixes they all tested right at 6.3 or whatever but then you do the same thing on number 7 and it appears to be low so you add more up.
You did the same thing and got a different result? So you adjusted it? When you track ins and outs you would recognize the tool may be the culprit.

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New2It said:

How and why would there be different settings or whatever? Isn't it a straightforward sort of thing? So quite possibly I've been doing this wrong the whole time? This begins to suck dude. I just want stuff that works properly

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NairnM16 said:

You get different reading depending on what the pen is showing

Ec = 1.0
Tds would be 1.0x500 =500tds
Ppm would be 1.0 x 700 = 700ppm

All the same thing just different measurements

I blame the Us for using anything but the metric system

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New2It said:

Thank you. That makes sense. But both say they're reading ppm

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Ninjadogma said:

I just came up with an idea for a good side hustle. There's a guy who sharpens clipper blades for pet trimmers and he announces when he's going to be at a particular store and people show up to get their clipper blades sharpened.

So a similar idea would to stock up on the standard solutions and deionized water and show up at a nursery on a Saturday to calibrate those pH and EC pens for $5 a pop.

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