Who has this meter ?

[trapgodd]

yeah so my meter has units . now it can either be ppm 300 ppm700 or ec i have been using 300 units then when I noticed my ppm were pretty high I moved it to 700 ppm on meter and bow my tds or ppm is 1500 from 1000

 

[trapgodd]

 

[trapgodd]

I'm sorry guys is 500ppm so the ratio is 2.4 ec x500 =1200 ppm (500ppm scale )

the 700 goes as this
2.4 ec x 700 =1680 ppm so my question is what scale so I use for general hydroponics flora series nutrients

 

[TorturedSoul]

yeah so my meter has units . now it can either be ppm 300 ppm700 or ec i have been using 300 units then when I noticed my ppm were pretty high I moved it to 700 ppm on meter and bow my tds or ppm is 1500 from 1000

I think you're talking about a conversion factor. All EC/"TDS" meters measure EC. When PPM display is desired, the meter simply multiplies the (measured) EC by the conversion factor. But that's an imprecise thing. The things in your nutrient solution that'll register on an EC meter (nutrient salts, metals, et cetera)... They all read just a little bit different from each other. Most meters have two choices for a conversion factor - you pick the one most relevant to what you've got in the solution. I don't suppose it matters a great deal which CF you use, really - as long as you use the same one each time. You'll still be able to track trends (This solution is stronger than the one I mixed up last week, the plants are using more water than nutrients, et cetera).

Most nutrient companies that use PPM in their nutrient calculators will either list the suggested conversion factor on their website or at least tell you in an email. Many either just use EC for it or offer the choice in the nutrient calc. I think EC seems to be more popular in Europe and other civilized lands, lol, and PPM seems to be a North American thing, mainly.

 

[trapgodd]

I think you're talking about a conversion factor. All EC/"TDS" meters measure EC. When PPM display is desired, the meter simply multiplies the (measured) EC by the conversion factor. But that's an imprecise thing. The things in your nutrient solution that'll register on an EC meter (nutrient salts, metals, et cetera)... They all read just a little bit different from each other. Most meters have two choices for a conversion factor - you pick the one most relevant to what you've got in the solution. I don't suppose it matters a great deal which CF you use, really - as long as you use the same one each time. You'll still be able to track trends (This solution is stronger than the one I mixed up last week, the plants are using more water than nutrients, et cetera).

Most nutrient companies that use PPM in their nutrient calculators will either list the suggested conversion factor on their website or at least tell you in an email. Many either just use EC for it or offer the choice in the nutrient calc. I think EC seems to be more popular in Europe and other civilized lands, lol, and PPM seems to be a North American thing, mainly.

thank you torturedsoul ! I was concerned I moved my plant to my 5 gallon system at about 1300 ppm it's been drinking more water than lately I think it's had enough nitrogen but then again I have stressed plant last few weeks with supercropping and lst. I think thus strain may just want it at that level I haven't had sifna,of burn,yet my oh just dropped significantly as water level dropped I knew I was becoming more concentrated. I just had some worries that's all . now,I plan to switch her nutes over tonight to flower but keep light scedusl the same for a week then switch to 12 12

 

[TorturedSoul]

This may help explain things a little better than I did:

EC vs. TDS


A quick answer to why we should use EC instead of TDS

The debate over EC and TDS has been an ongoing issue for a long time. These two measurements are used to determine the strength of hydroponic solution. Although they are widely used they should only be used as a guideline and you should always follow mixing instructions on the label of you nutrient.

EC stands for Electrical Conductivity and is measured in mS/cm or millisiemens per centimeter. TDS stands for Total Dissolved Solids and is measured in PPM or parts per million. TDS is acquired by taking the EC value and performing a calculation to determine the TDS value. Because TDS is actually a calculation it is really only a guess at what the nutrient concentration is. On top of that, there are three different conversion factors to determine TDS and different manufacturers use different conversion factors. In other words you could test the same solution with two different meters and get two totally different readings. But the EC is read the same by all meters the only difference is the conversion factor.


Some additional information for the geeks like us

First of all lets talk about the differences and similarities between EC and TDS. We all know that they are both a measure of the amount of dissolved solids in your nutrient solution. This measurement is used by growers to get an idea of how much nutrient is present in the solution. By maintaining the correct level of nutrients in the solution your plants will achieve maximum results. This all sounds very important but there are some major differences between the different meter manufacturers. Some of you may have noticed that some calibration solutions that are marked to read at a certain TDS may actually read different from meter to meter. This is where the problem begins.

Some of you may have not even heard of EC and others may have heard of it but do not even know what it is. Unfortunately many growers in the United States have become very accustomed to using the TDS scale while in most other countries, including Europe, they don't use anything but EC. The fact is that TDS is actually a result of a calculation from EC. The problem is lack of consistency among manufacturers when it comes to conversion factors. This is where it may get a little confusing. Most meter manufacturers in the hydroponics industry use one of two conversions. There is the 442 conversion (40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride) which some say is the closest thing to a hydroponic solution. The 442 conversion is approximately 700 x EC in millisiemens (mS). Then there is the NaCl conversion (sodium chloride) which others say is the closest thing to a hydroponic solution. The NaCl conversion is approximately 500 x EC in millisiemens (mS). You can see where the confusion comes from because the same solution will read 2100 ppm on one meter and it will read 1500 ppm on the other. That is a difference of 600 ppm which as many of you know could be devastating. Both meters are functioning correctly they are just calculating the TDS using a different formula. So, if you do not calibrate your meter using the correct calibration solution your meter could give you a very inaccurate reading.

The solution is simple, use EC. With EC, no conversion is required so all meters will read the same regardless of the manufacturer.

Here is a chart showing some sample measurements:

mS	µS	NaCl Conv.	442 Conv.
1.0 mS	1000 µS	500 ppm	700 ppm
1.5 mS	1500 µS	750 ppm	1050 ppm
2.0 mS	2000 µS	1000 ppm	1400 ppm
2.5 mS	2500 µS	1250 ppm	1750 pp

 

[Skunkworkz]

my question is what scale so I use for general hydroponics flora series nutrients

Use "442" conversion (700) which is the most accurate for GH nutes-but the best, most accurate way is to simply read straight EC.