Why PPM?

  • Thread starter JayBee
  • Start date
  • Tagged users None
JayBee

JayBee

International Toker
Supporter
744
28
Can some one explain to me why we talk about ppm or even have it on our meters? What I mean is that as we all know PPM depends upon different meters conversion rates. SOOOO... It seems to me that all meters have the same readings for EC and CF and all manufacturers have different readings for PPM.

SO why does anyone talk about ppm? Does this make sense to anyone? Cause it seems totally coo-coo bananas to me. Wouldn't it make sense fore everyone to just use ec or cf as standard for online discussions, or is there something I am missing?

:icon_cookie:

jb
 
C

cecilc

8
0
I have always found that if ya have a good water supply, keep the root zone nice and shiny and happy and clean, dump and refill buckets, reservoirs, etc. regularly, that ya don't have to sweat the meters too much. Many will say the opposite. It certainly can't HURT to have ultimate control over all aspects of the plant's life, and dial in everything down to the last detail, but for my 2 cents I say it's down the ladder a few rungs in importance.

PS. After rereading your post I see I missed the point. I'll leave it cause I need 7 more posts to chat, lol. ;)
 
Rootbound

Rootbound

Supporter
2,634
263
I use PPM meter. EC meters have different conversion rates depending on where you are from, and that gets confusing. I was not aware there was different conversion rates for PPM. Parts per million should be exactly what it is- Parts Per Million. This is just my opinion. Anyone else? ROOT
 
S

Slick

75
8
EC meters measure directly so the figures recieved will be identical for solutions measured with different brands of meter. TDS meters use various algorithms to calculate PPM which is why its always a good idea to give the conversion factor your meter uses when giving your PPM. It is impossible to get a 100% accurate PPM reading unless you are in a lab as it's always calculated from EC when using a meter.

To answer the question though...people use different measurements simply because that's what they are used to much like inches and centimeters; PPM in the States, EC in Europe.
 
P

pikes peak 69

226
18
I agree with this statement. ppm is calculated from the EC, you have a conversion factor involved. Usually .5 or .7. ie; EC of 1.8 would be 900 ppm @ .5 factor.

pp69
EC meters measure directly so the figures recieved will be identical for solutions measured with different brands of meter. TDS meters use various algorithms to calculate PPM which is why its always a good idea to give the conversion factor your meter uses when giving your PPM. It is impossible to get a 100% accurate PPM reading unless you are in a lab as it's always calculated from EC when using a meter.

To answer the question though...people use different measurements simply because that's what they are used to much like inches and centimeters; PPM in the States, EC in Europe.
 
JayBee

JayBee

International Toker
Supporter
744
28
But everyone in the states is using different meters with different ppm- its like if an inch was different size in every state in usa, would be crazy! :)

I only have truncheon so maybe i dont understand, do the meters in states ONLY give info in ppm? Or is there an option to see EC?
 
S

Slick

75
8
Whether you can see both EC and PPM would depend on the meter spec I reckon but I don't really have any experience with anything other than a Bluelab truncheon, they have EC and PPM (ECx500, ECx700).

Found this during my research on this stuff and what one to buy, some may find it handy.
 
PPM EC C
SKUNK420

SKUNK420

51
8
i see ppm like millimeters and EC like inches or 1/4 inches. while EC is easier to overall use since you don't have to worry about conversion factors and some math.

look at the chart above posted by Slick. it shows what i mean.
 
R

Redux

Guest
It's very simple...EC readings are universal. PPM's are based on a conversion formula/factor from EC. If you're talking EC with someone you're talking the same language. If you're talking PPM's then ya gotta know what the CF is.
 
S

Slick

75
8
It's very simple...EC readings are universal. PPM's are based on a conversion formula/factor from EC. If you're talking EC with someone you're talking the same language. If you're talking PPM's then ya gotta know what the CF is.

EC and CF are the same thing, just different terms; EC is Electrical Conductivity and CF is Conductivity Factor.
 
J

johnnyballbag

Premium Member
Supporter
305
0
Why does it really matter? You're only using a meter to get a rough idea of what your solution is. If you don't like ppm then simply buy a meter that doesn't display or measure in ppm. Break the definition of each term. Parts per million is exactly that, how many parts per million are present. That's all it tells you, period. But the electrical conductivity and conductivity factor are measures of how good of a conductor the solution is. The more dissolved solids, the higher its conductivity. Water does NOT conduct electricity. If you had 100% pure H2O it wouldn't conduct shit. So what does that even tell you? Doesn't tell you WHAT is in the water. Nor does it tell you the amount of non-dissolved solids either, so really the CF and EC are converted measurements in their own right.
 
Rootbound

Rootbound

Supporter
2,634
263
Why does it really matter? You're only using a meter to get a rough idea of what your solution is. If you don't like ppm then simply buy a meter that doesn't display or measure in ppm. Break the definition of each term. Parts per million is exactly that, how many parts per million are present. That's all it tells you, period. But the electrical conductivity and conductivity factor are measures of how good of a conductor the solution is. The more dissolved solids, the higher its conductivity. Water does NOT conduct electricity. If you had 100% pure H2O it wouldn't conduct shit. So what does that even tell you? Doesn't tell you WHAT is in the water. Nor does it tell you the amount of non-dissolved solids either, so really the CF and EC are converted measurements in their own right.


That is what I was trying to say earlier JBB. Parts per million is exactly that PARTS PER MILLION. no conversion factor involved. Well said JBB. ROOT
 
J

johnnyballbag

Premium Member
Supporter
305
0
Thanks RB. I just think ppl put way more stock into that than they should. Relying on a meter will never teach you about your plants. It'll just teach you how to use a meter. Just my opinion of course...
 
R

Redux

Guest
I'm bad for mixing Conductivity Factor with Conversion Factor. Yes Conductivity Factor and EC is really nothing more than where you place the decimal point...with milli and micro siemens and all that kind of stuff...not to be confused with Conversion Factor though.

That is what I was trying to say earlier JBB. Parts per million is exactly that PARTS PER MILLION. no conversion factor involved.
PPM is based on EC. To convert from EC (or Conductivity Factor...which is not to be confused with Conversion Factor) to PPM you use a particular Conversion Factor of like .5 so an EC, which is a standard system of measure and not arbitrary like PPM which is based on a Conversion Factor, of say 1000 is the exact same thing as 500 PPM using a Conversion Factor of .5...ya dig?
 
F

Fear

Guest
Well put johnny! I use my ph meter to make sure verything is being absorbed and take notes of the ppm and ec during the grow just to monitor.
 
J

johnnyballbag

Premium Member
Supporter
305
0
I dig. But how much electricity my water conducts still doesn't really tell me shit about what i'm giving my plant. I mean i've got a meter, but i only use it a few times per crop at most.
 
S

Slick

75
8
The whole reason I have an EC meter is so I can monitor accurately when I have to add nutrients. It doesn't tell me what they are eating but it does tell me how heavily and for that I find it invaluable. I would be lost without mine and respect to anyone growing hydro without one.

I'm no expert obviously but not using a meter is analogous to not checking the oil or water in a car regularly I reckon, no doubt lots of people do it with no problems at all but thier cars would probably run better if they checked more often.

Just my 2 cents.
 
R

Redux

Guest
SO why does anyone talk about ppm? Does this make sense to anyone? Cause it seems totally coo-coo bananas to me. Wouldn't it make sense fore everyone to just use ec or cf as standard for online discussions, or is there something I am missing?
Going back to the original question...once I learned about EC I dropped the PPM thing as it is confusing IMO. You can have 3 dif PPM meters and all will show a dif PPM reading yet the EC will be the same.

When I was trained in hydro it was by regulating the formula through using EC. Once I got it dialed in better I would go through half a 100 gal res with only minor drifts in EC and pH. In fact the person that taught me grew for years only checking EC and did not start monitoring pH until I started working with her. Funny thing is when she would fill a res and adjust the mix through EC the pH would drop to 5.6 and never went over 6.0 as the res was used up...lol. She was perfect on pH the whole time and never knew it...lol.
 
J

Jalisco Kid

Guest
A ppm/ph meter is important for certain types of grows,aero and buckets sys come to mind. There are days my girls will suck down 250 ppm over night and that at a 3.5 gal per plant rez. . Unless you run a drain to waste they come in real handy. I give more importance to my Cardy pH meter. JK
 
J

johnnyballbag

Premium Member
Supporter
305
0
I never meant to say they're not important, more just trying to point out that neither EC, CF or ppm is perfect or in any way better than the other. To be truly honest they all are false numbers in one way or another. I use my meter and the numbers it shows me as a baseline, something to compare to i guess. If my meter says 1000ppm at one point and then 1200ppm at another point, then that tells me there's been a change. Doesn't tell me anything more than that. Unless for some reason you use several different meters from different manufacturers randomly for the same grow, it's all relative.
 
Top Bottom