Be skeptical of your measuring tools

[Billy the Mountain]

I stumbled across a Vivosun EC meter I forgot I owned; I think it was bundled with a purchase a few years back.
It (and its clones) seem to be quite popular, and the conventional wisdom is that it's just a conductivity meter and a cheap one should suffice.
I thought I'd give it a try and calibrated it with some 1000ppm calibration fluid. I also did the same my Com-80 EC meter.
The Com-80 hasn't been calibrated in a year at best, but was spot-on. The vivosun was off, but was able to calibrate it and their measurements agreed; for a day.
Today I mixed up a small batch of nutes and measured the EC; I know from experience it should be about 1.2 and rarely actually measure it.
I used the same two meters and the Vivosun is off by 50% even though it was calibrated yesterday; that's dismal.

An inaccurate measurement is worse than no measurement. Even though conductivity meters are very simple in design, don't assume a cheap one works. Too bad EC drops aren't a thing.

I'm convinced a good percentage of problems start from bad measurements and the actions taken in response.

Rant mode off.


18 hours after calibration:

 

[Hollatchaboy]

I stumbled across a Vivosun EC meter I forgot I owned; I think it was bundled with a purchase a few years back.
It (and its clones) seem to be quite popular, and the conventional wisdom is that it's just a conductivity meter and a cheap one should suffice.
I thought I'd give it a try and calibrated it with some 1000ppm calibration fluid. I also did the same my Com-80 EC meter.
The Com-80 hasn't been calibrated in a year at best, but was spot-on. The vivosun was off, but was able to calibrate it and their measurements agreed; for a day.
Today I mixed up a small batch of nutes and measured the EC; I know from experience it should be about 1.2 and rarely actually measure it.
I used the same two meters and the Vivosun is off by 50% even though it was calibrated yesterday; that's dismal.

An inaccurate measurement is worse than no measurement. Even though conductivity meters are very simple in design, don't assume a cheap one works. Too bad EC drops aren't a thing.

I'm convinced a good percentage of problems start from bad measurements and the actions taken in response.

Rant mode off.


18 hours after calibration:
View attachment 5321865

That's why I don't mess around......

 

[manfredo]

Funny you say this. I have that same exact Vivosun EC meter, that also came in a bundle about 3-4 years ago.

I never had a need for one until recently when I started growing in coco. I thought this old Vivosun POS can't possibly be accurate, so I spent $100 on a Bluelab.



Turns out my Vivosun was spot on, and the Blulab only reads in increments of 100, so I am returning it....

Another member told me the basic EC meters are typically accurate, unlike cheap PH meters.

Anyways, did you check the batteries in the Vivosun that's been sitting for "a few years"? That might be the problem.

 

[Billy the Mountain]

Funny you say this. I have that same exact Vivosun EC meter, that also came in a bundle about 3-4 years ago.

I never had a need for one until recently when I started growing in coco. I thought this old Vivosun POS can't possibly be accurate, so I spent $100 on a Bluelab.

View attachment 5321875

Turns out my Vivosun was spot on, and the Blulab only reads in increments of 100, so I am returning it....

Another member told me the basic EC meters are typically accurate, unlike cheap PH meters.

Anyways, did you check the batteries in the Vivosun that's been sitting for "a few years"? That might be the problem.

Yup, brand new 2032 battery. The first one I had was P.O.S. as well, and then bought a COM-80 meter. It's a reasonable assumption that a simple device that's just measuring current would be accurate, but they're not. One other gripe about the Vivosun family of EC meters is the 4 digit disply; it simply doesn't have the resolution to use 4 digits and you can see it move up/down in large increments; I'd bet big its internal resolution is much lower.
If yours works reliably, consider yourself fortunate and calibrate it often.
The fact that the Truncheon only displays in increments of 0.1 ms is not an issue for hydroponics; whether it can do so consistently is.

 

[manfredo]

Yup, brand new 2032 battery. The first one I had was P.O.S. as well, and then bought a COM-80 meter. It's a reasonable assumption that a simple device that's just measuring current would be accurate, but they're not. One other gripe about the Vivosun family of EC meters is the 4 digit disply; it simply doesn't have the resolution to use 4 digits and you can see it move up/down in large increments; I'd bet big its internal resolution is much lower.
If yours works reliably, consider yourself fortunate and calibrate it often.
The fact that the Truncheon only displays in increments of 0.1 ms is not an issue for hydroponics; whether it can do so consistently is.

Yeah don't get me wrong, I'm not a fan of Vivosun, and I normally avoid their stuff.

Mine seems to handle the 4 digits fine though, and doesn't jump around.



But yeah, I don't trust it!!

 

[Billy the Mountain]

Yeah don't get me wrong, I'm not a fan of Vivosun, and I normally avoid their stuff.

Mine seems to handle the 4 digits fine though, and doesn't jump around.

View attachment 5321911

But yeah, I don't trust it!!

Sure, it will display a 4-digit result, but you'll never see the measurement change by a single digit, not even close.
I'm not shitting on Vivosun either, but a tool that can't be trusted is a useless tool.

 

[Fangthane]

Too bad EC drops aren't a thing.

More and more, I'm thinking coco may actually end up being my groove. Once my tents clear out and cooler weather is here, I'm planning on doing a coco run to see how it suits me. I have a TDS pen I rarely use; and have gotten by just fine with my GH pH test solution so far. I'm thinking that if I'm gonna be doing hydro on a regular basis, I should probably bite the bullet and buy some decent meters. I've just had shit luck with them so far and hate having to rely on dodgy tech.

In soil, I kinda just pick my starting point as X% of the recommended dosage and make adjustments from there, without typically dusting off the TDS pen. I'm guessing that may not be a great recipe for success in hydro?

 

[Billy the Mountain]

More and more, I'm thinking coco may actually end up being my groove. Once my tents clear out and cooler weather is here, I'm planning on doing a coco run to see how it suits me. I have a TDS pen I rarely use; and have gotten by just fine with my GH pH test solution so far. I'm thinking that if I'm gonna be doing hydro on a regular basis, I should probably bite the bullet and buy some decent meters. I've just had shit luck with them so far and hate having to rely on dodgy tech.

In soil, I kinda just pick my starting point as X% of the recommended dosage and make adjustments from there, without typically dusting off the TDS pen. I'm guessing that may not be a great recipe for success in hydro?

A servicable EC meter isn't expensive, I think the Com-80 is about $30. I've had mine for a few years, it's both reliable and accurate.
Switching to coco coir a few years ago was the best move I've made since growing DWC for many moons, I wish I'd done so sooner.

It depends on your nutes, but 50% of the recommended dose is a good place to start.

 

[manfredo]

More and more, I'm thinking coco may actually end up being my groove. Once my tents clear out and cooler weather is here, I'm planning on doing a coco run to see how it suits me. I have a TDS pen I rarely use; and have gotten by just fine with my GH pH test solution so far. I'm thinking that if I'm gonna be doing hydro on a regular basis, I should probably bite the bullet and buy some decent meters. I've just had shit luck with them so far and hate having to rely on dodgy tech.

In soil, I kinda just pick my starting point as X% of the recommended dosage and make adjustments from there, without typically dusting off the TDS pen. I'm guessing that may not be a great recipe for success in hydro?

It's a totally different beast, for sure! I just am finishing up my 1st run, and i learned a lot....Made a lot if mistakes. Built a simple drain to waste setup.

This was a good read....I read the entire thread.

A few things that I've learned about growing in coco with a drip systm DTW

Ok let me chime in with what I've learned about coco. The majority of my growing life was spent growing with organic soil, I used bio bizz nutes with compost teas and it was great, I grew in 12Ltr pots and watered every 2 days, wet-dry cycles..... Now I was happy growing like that but then I...

www.icmag.com

 

[7CardBud]

I always check new nutrient mixes in HydroBuddy. If I'm off by more than 0.1EC I know there is an error somewhere.

Also still using the cheapo HM Com-80 meter after 4 years.

 

[amneziaHaze]

As long as you dont stop using them for a long period of time cheap asian shit works great.but let it dey for 3 months and it gets fucked

 

[calvin.m16]

This is why i have switched to using pH drops and I feed nutrients by volume (grams/cups) not by EC/PPM. I have a 36 plant coco garden and can't remember the last time I used a battery powered device to measure pH or nutrients and my shits boomin.

 

[manfredo]

This is why i have switched to using pH drops and I feed nutrients by volume (grams/cups) not by EC/PPM. I have a 36 plant coco garden and can't remember the last time I used a battery powered device to measure pH or nutrients and my shits boomin.

What are you feeding them....I'm new to coco, did my first run using GH Flora, but not without issues.

 

[calvin.m16]

What are you feeding them....I'm new to coco, did my first run using GH Flora, but not without issues.

General Hydroponics Armor Si 5ml/gal
General Hydroponics MaxiBloom 7 to 8 grams per/gallon (totally base off plants, if they are light green then add more, dark green add less)

MaxiBloom is designed to measure in volume too, so once you figure out 3/4 cups weighs roughly 220 grams per example you can scoop that same amount every time without weighing.

I get duke nuke em cannons without any additives and I use RO filtered water hence all the armor si, if you have high pH water then skip the armor si. It's literally my pH UP but I do think the silica helps the plant somewhat.

 

[manfredo]

General Hydroponics Armor Si 5ml/gal
General Hydroponics MaxiBloom 7 to 8 grams per/gallon (totally base off plants, if they are light green then add more, dark green add less)

MaxiBloom is designed to measure in volume too, so once you figure out 3/4 cups weighs roughly 220 grams per example you can scoop that same amount every time without weighing.

I get duke nuke em cannons without any additives and I use RO filtered water hence all the armor si, if you have high pH water then skip the armor si. It's literally my pH UP but I do think the silica helps the plant somewhat.

Thanks for the quick reply, and I was thinking of trying MaxiBloom for the simplicity...Like you said, once you know your measurement it's the same every time.

I use RO water too, and I think that's where some of my issues are. I was adding Armor Si at 5 ml per gallon the first 2 weeks, then dropping to 2 ml, and ran into some deficiencies. I read some people use 5 ml per gallon start to finish.

Sounds a lot easier than this...and I am running into some weird burn / bleaching crap this new run already...Hence looking to change!

 

[VaSmile]

Your ph meter should only be used once.
Know you have one that is accurate.
Test your tap then make 1 gal of each your most common feed mixs. Slower measure how much ph adjustment is needed for each mix to get it to your target ph. Write it down. Return meter for refund. Now you have your recipe for each week, no need to test you know exactly what is required to hit your target ph for each feed and it will not change.

P.S. I'm ever lazier then that.

 

[Hollatchaboy]

Thanks for the quick reply, and I was thinking of trying MaxiBloom for the simplicity...Like you said, once you know your measurement it's the same every time.

I use RO water too, and I think that's where some of my issues are. I was adding Armor Si at 5 ml per gallon the first 2 weeks, then dropping to 2 ml, and ran into some deficiencies. I read some people use 5 ml per gallon start to finish.

Sounds a lot easier than this...and I am running into some weird burn / bleaching crap this new run already...Hence looking to change!

View attachment 5324318

You don't need all that. I just use flora micro, and flora bloom, with a dash of mgso4. H3ad formula. With ro water.

You could probably run just floranova bloom or maxibloom also. Looks like you have about 10-12 bottles too many.

 

[curious2garden]

Thanks for the quick reply, and I was thinking of trying MaxiBloom for the simplicity...Like you said, once you know your measurement it's the same every time.

I use RO water too, and I think that's where some of my issues are. I was adding Armor Si at 5 ml per gallon the first 2 weeks, then dropping to 2 ml, and ran into some deficiencies. I read some people use 5 ml per gallon start to finish.

Sounds a lot easier than this...and I am running into some weird burn / bleaching crap this new run already...Hence looking to change!

View attachment 5324318

From the pattern I believe the bleaching was your lights not your nutrients. Unfortunately once damaged the leaves never recover. I think you'd have a much easier time with only Flora Micro, Grow, Bloom and Ca/Mg to start. The others I've found to be not required.

The Maxi's are simple and you don't buy water. I still with Flora because that's all they had in '96 when I started. So it's dead simple for me. But I keep looking at Maxi.

 

[Fish scale]

If it's a few years old it's probably got salt build up on it which will mess with the readings. This is why you should wash your EC meter daily with clean tap water to prevent any salt build up.

 

[Cpappa27]

I stumbled across a Vivosun EC meter I forgot I owned; I think it was bundled with a purchase a few years back.
It (and its clones) seem to be quite popular, and the conventional wisdom is that it's just a conductivity meter and a cheap one should suffice.
I thought I'd give it a try and calibrated it with some 1000ppm calibration fluid. I also did the same my Com-80 EC meter.
The Com-80 hasn't been calibrated in a year at best, but was spot-on. The vivosun was off, but was able to calibrate it and their measurements agreed; for a day.
Today I mixed up a small batch of nutes and measured the EC; I know from experience it should be about 1.2 and rarely actually measure it.
I used the same two meters and the Vivosun is off by 50% even though it was calibrated yesterday; that's dismal.

An inaccurate measurement is worse than no measurement. Even though conductivity meters are very simple in design, don't assume a cheap one works. Too bad EC drops aren't a thing.

I'm convinced a good percentage of problems start from bad measurements and the actions taken in response.

Rant mode off.


18 hours after calibration:
View attachment 5321865

Thats a really good point. I wonder if half of these cannabis plant problems and burns are from faulty equipment. Also I noticed those little RH and temp meters used for curing are very inconsistent.

So which one is right lol