What's more important EC or PPM?

Cigarz

Active Member
I noticed with a EC of 1.3-1.7 I can't get a PPM higher than 400-500... But recommendation is 700-800 for veg, what do I do?
 
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Tracker

Well-Known Member
The ppm value your meter tells you is a derived value based on the electrical conductivity EC of the solution. EC is a more direct measurement of the ability of the solution to conduct electric current.

Different manufacturers use different scale factors to convert the EC measurement to ppm. You need more info on the specifications of your meter to know whats going on there.
 

lusidghost

Well-Known Member
800 is hot for a vegging plant. What do you mean you can’t get it higher than 500?

edit: never mind. I understand what you mean. You can’t get it higher within that EC range.
 

Cigarz

Active Member
800 is hot for a vegging plant. What do you mean you can’t get it higher than 500?

edit: never mind. I understand what you mean. You can’t get it higher within that EC range.
Yes... which is why I ask whats more important, PPM or EC? I can't have both, my nutrients require EC of 1-1.7 but in order to reach that PPM won't go above 500... So what do I do to correct this? or I cant do anything?

From what I'm reading 700-800 is best PPM for veg? and 1000+ for flower. 600 or so for seedlings/clones. No way I can hit anywhere near 700-800 ppm with a EC of 1-1.7.

Which is more important and which should I go by?
 

Cigarz

Active Member
The ppm value your meter tells you is a derived value based on the electrical conductivity EC of the solution. EC is a more direct measurement of the ability of the solution to conduct electric current.

Different manufacturers use different scale factors to convert the EC measurement to ppm. You need more info on the specifications of your meter to know whats going on there.
Not sure, this is the one I got.


IT does PPM, and uS/mS and Temperature. It reads around 800 on the uS/mS side and around 400-500PPM on the PPM side. so I'm confused now lol
 

twentyeight.threefive

Well-Known Member
Not sure, this is the one I got.


IT does PPM, and uS/mS and Temperature. It reads around 800 on the uS/mS side and around 400-500PPM on the PPM side. so I'm confused now lol
I don't think you are understanding the basics. ppm = EC. It's just a different scale. Like celsius and fahrenheit. 0 C = 32 F. 500 ppm = 1 EC on 500 scale. There is also a 700ppm scale but most readers are 500 scale.

ec_ppm_conversion_chart.png
 

twentyeight.threefive

Well-Known Member
I gather that, how do I figure out what scale to use? why does the meter have both PPM and EC if it's the same thing?
You have to reference the meter you purchased for what ppm scale it reads. Why have a thermometer that reads C and F. I generally never reference ppm, for my growing needs I measure everything in EC, it's universal.
 

Cigarz

Active Member
I don't think you are understanding the basics. ppm = EC. It's just a different scale. Like celsius and fahrenheit. 0 C = 32 F. 500 ppm = 1 EC on 500 scale. There is also a 700ppm scale but most readers are 500 scale.

View attachment 4889632
If this is the case then why @ 1.6-1.7EC it reads around 400PPM and not 900? Is that because it uses .5 instead of .7? This is what confuses me.
 

twentyeight.threefive

Well-Known Member
If this is the case then why @ 1.6-1.7EC it reads around 400PPM and not 900? Is that because it uses .5 instead of .7? This is what confuses me.
You'd have to share a picture of both readings. If one says 1.6 EC then it's either 800ppm, 1024ppm, or 1120 ppm. If it's none of those it either needs to be calibrated or returned if it can't be calibrated.
 
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