tds&ec pen question
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mudballs
Well-Known Member
depends which country the pen was made in. all pens use EC then convert to get ppm. the chart shows each country of origins conversion. if you know the manufacturer or country that tells you which column on the chart to use. if it US made or the instructions mention US then that tells you to use the US conversion.
Jimdamick
Well-Known Member
EC is a European measurement. PPM is an American measurement. If you buy your nutes in France or Great Britain, they ( the manufacturer) will give their measurements in EC (electrical conductivity). You buy that product in the US or Canada, you get recommended levels in PPM (parts per million). It all depends on where you live. EC is more precise, too precise in my book. PPM is close enough in my book. PPM seedling- 300- 400 PPM ( I feed immediately at 1 week)/ 2nd week - 400- 450 / 3rd week 400- 500 / 4th week 600- 700 / 5th week Bloom- 900- 1000 PPM / 6th week 1100 to 1300 ( average plant ok, pushing it on a lite feeder) 7th week- 900 ppm/ 8th week 400 PPM/ last 2 weeks, no added ferts (enough in root system) I drop out all nutes at least 1 week before harvest, usually 2 weeks. This has worked for me in both hydro and soil, with no burn. I hope I have helped
mudballs
Well-Known Member
ah sorry bout that.here's a post i made to a similar thread.
those are the conversion factors various manufacturers use. to get ppm pens actually use EC and convert to ppm but not all conversions are the same. the pen you have says to use US conversion. i'll have to look it up but it's the lowest of the conversions i think
USA 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
European 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
Australian 1 ms/cm (EC 1.0 or CF 10) = 700 ppm
http://www.kindgreenbuds.com/marijuana-grow-guide/difference-between-ppm-and-ec/
so you use the chart column with the .5 conversion.either hanna or dutchmaster both the same.
MuckyDucky
Well-Known Member
If your EC pen is reading 411ec then divide 411 by 100 an look at the EC ms/cm .41 entry or divide by 10 and look at 4 in the CF column. Don't get confused by European and US EC. They are basically the same. It is the PPM measurements that can be confusing... most of the time when you read about PPM it never mentions whether it Hanna (EC * .5) or Truncheon (EC *.7). I bought a Milwaulkee 802 and then found out it had a .67 conversion. Luckily it also has EC and that is all I use now.
FilthyFletch
Mr I Can Do That For Half
If your in the use all you really need to be concerned about is ph and ppm numbers. the EC/tds is more a concern to euro growers as they seem to use it more of a standard then in the US. Keep ph in hydro around 5.5 and thats good and your ppm is nutrient maker specific per stage of growth.
WeedFreak78
Well-Known Member
Wrong and Wrong. EC, TDS and PPM are all the same thing just expressed differently. PPM is a measurement of TDS based off a solutions EC. ALL meters, no matter where they are made, read EC then convert to ppm, based off of a conversion factor ( usually .5 or .7) depending on how the meter is calibrated, some meters allow you to choose which CF you want to use. In order to accurately mix nutrients you need to know if a manufacturer is using a .5 or .7 EC to get their recommended PPM levels. EC is a better measurement, 1.0 EC is 1.0 EC no matter where you live.
read and learn:http://www.kindgreenbuds.com/marijuana-grow-guide/difference-between-ppm-and-ec/
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ttystikk
Well-Known Member
Everyone who is telling you not to use EC is giving you bad advice.
No one above is a chemist, and thank God a chemist explained it to me;
EC = electrical conductivity. This is the actual measurement your instrument makes, NO MATTER THE COUNTRY OF ORIGIN. THAT'S JUST BULLSHIT.
PPM scales vary! Why? Because the actual parts per million of different materials in a water based solution vary in terms of their EC reading. Standard PPM scales include the common 500 scale, the H&G preferred 700 scale, the less common 740 scale- and there are others. In fact, there's a PPM scale for damn near every nutrient in your solution- and they're all different. Why? Because the baseline mineral used to set the scale is different. But your nutrient solution is a mix, so...
USE EC. DON'T BELIEVE ANYONE WHO TELLS YOU NOT TO. EC NEVER CHANGES AND THERE IS ALWAYS A CONVERSION TO EC FROM WHATEVER SCALE THEY'RE USING.
It's almost a joke here in Colorado; you can tell if someone it's a pro or not by whether they converse in EC or PPM. If they talk PPM, it's amateur hour. Use EC if you want to be taken seriously.
No one above is a chemist, and thank God a chemist explained it to me;
EC = electrical conductivity. This is the actual measurement your instrument makes, NO MATTER THE COUNTRY OF ORIGIN. THAT'S JUST BULLSHIT.
PPM scales vary! Why? Because the actual parts per million of different materials in a water based solution vary in terms of their EC reading. Standard PPM scales include the common 500 scale, the H&G preferred 700 scale, the less common 740 scale- and there are others. In fact, there's a PPM scale for damn near every nutrient in your solution- and they're all different. Why? Because the baseline mineral used to set the scale is different. But your nutrient solution is a mix, so...
USE EC. DON'T BELIEVE ANYONE WHO TELLS YOU NOT TO. EC NEVER CHANGES AND THERE IS ALWAYS A CONVERSION TO EC FROM WHATEVER SCALE THEY'RE USING.
It's almost a joke here in Colorado; you can tell if someone it's a pro or not by whether they converse in EC or PPM. If they talk PPM, it's amateur hour. Use EC if you want to be taken seriously.
Jimdamick
Well-Known Member
I thought I said that PPM is more widely used in the US, and EC is a Euro thing. Of course the are the same thing, just like most Americans use MPH vs kilometers an hour in Europe, same shit different name. I have been growing for a little while, and I have never seen a formula measured in EC in this country. When I set my meter, I have the choice between EC or PPM. If I calibrate my meter to EC and it reads 1.5 the number will represent the same amount of nutrients as say 500 PPM. Read a calibration solution, run your finger across the label, set you temp, and 1.5 EC will be the same as 500 PPM, or am I wrong, again.
WeedFreak78
Well-Known Member
Similar, but not the same, KPH and MPH both measure velocity, but 5 mph isn't the same as 5 kph because they are measured with slightly different parameters,1 KM does not equal 1 Mile. Same thing with PPM's because they are calculated using a formula based off EC.
I just took a quick look at GH's website for reference, they use a .5CF for their PPM readings, if you mixed your PPM's on a .7CF pen your nutrient solution wouldn't be anywhere close to what they recommend even though your pen was reading XXXppm that the schedule said.
Lets take the same nutrient solution @1.0EC, 1.0 [email protected] cf=500ppm, 1.0 [email protected]=700ppm, the EC is the same but your [email protected] looks like it's almost 50% stronger even though they both have the same amount of TDS in the solution, remember TDS is directly correlated to EC. You need to know which CF your meter uses, and which CF your nutrient supplier uses then you can figure out what ppm reading your shooting for. I could be wrong but I believe gas analysis is the only true way to measure actual PPM of a solution, that's why we use meters the calculate PPM based off EC.
there is a 40% difference in readings from .5CF to .7CF, at low nute levels it isn't as big of an issue as at high levels.
[email protected]=50ppm [email protected]=70ppm
[email protected]=500ppm [email protected]=700ppm
[email protected]=1000ppm [email protected]=1400ppm
take this example
[email protected]=1.0 EC [email protected]=.7 EC
same ppm but at .7CF it's actually a weaker solution.
So EC is the only true way to measure the TDS in a solution, otherwise if you don't know the different CF's used by your meter manufacturer and your nutrient manufacture you could be 40% stronger or weaker on your solutions.
I'm no scientist, i just stayed at a holiday inn once...
ttystikk
Well-Known Member
If this were the case, then Colorado should share borders with Switzerland.
This is not the case.
USING A 500 SCALE, 1 EC = 500 PPM. I'm not aware of a scale that equates 1 EC to 1500 ppm.
Again, since the PPM scales vary, USE EC. No matter which side of the Atlantic you're on, lol
WeedFreak78
Well-Known Member
Is there a sticky about this anywhere?? Seems like this causes much confusion and something under the nutrient subsection explaining the correlation between EC,TDS, PPM, CF is needed. Everything I know about nutrient EC, TDS, PPM I've learned in the last week or so, mainly through RIU forums, but it was randomly posted in various threads.
Jimdamick
Well-Known Member
I guess I have been doing it wrong. I use Technaflora BC products,, which states that 1 part A + 1 part B SHOULD give me a reading of 700 ppm OR 1.4 EC per gallon of water. I calibrate my Greenlee PH/PPM/EC meter using Hanna TDS calibration solution at 25 Celsius/77.0 Fahrenheit. I calibrate until I achieve 1450 PPM and then, when I get that number, I switch over to EC and get a reading of 2.9 which matches my chart. So, what I figured, stupid me, if I wanted a PPM of say 1450 PPM, but my calibrated meter stopped giving me a PPM readout, if I got a reading of 2.9 EC, that would equal 1450 PPM. I am a dick, and I thank you for straightening me out. That's what I luv about this site, you learn more each and every day.
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