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Growroom Design
#61

An EC of 2200 is exactly equal to an EC of 2.2. One is stating it in microsiemens (uS) and the second one is in milisiemens (mS).

A milisiemen is 1/1000 of a siemen. A microsiemen is 1/1,000,000 of a siemen. One milisiemen is exactly 1000 microsiemens.

Its just like one meter = 1000 milimeters = 1,000,000 microns or micrometers.

So 2.2mS (milisiemens) is exactly the same thing as 2200 uS (microsiemens), and both are equal to a PPM of 1100 on the 500 scale or 1540 on the 700 scale. All of those are exactly the same. Its just different ways to say it.

Most meters automatically switch back and forth from mS to uS depending on how strong the solution is. My Apera displayed uS from 1 to 999, then switched automatically to mS when the number got to 1000.

That chart you linked to above shows EC in milisiemens - mS /cm.

#62

Yeh it also shows CF (conductivity factor) and many folks confuse the two which is what my post was really trying to point out. You are of course right that the unit for measuring conductivity is the siemen but for the sake of avoiding confusion i think growers should stick to either EC or PPM.

Most manufacturers these days use EC (electrical conductivity), here is a statement from AN for their floranova mud - ā€œfor young plants use, an EC = 1.2 - 1.5ā€

This can obviously be expressed as CF = 12 - 15 if you want to confuse folk :laughing:

Maybe you can tell @ Fisch what his EC of 2200 is equal to in CF or PPM because most conversion charts only go as high as EC 3.2 (which to be honest is so high itā€™s toxic to plants). Iā€™m not sure if even neat, undiluted nutrients would measure as high as EC 2200 :joy:

I know you qualified it but i think this statement will almost certainly lead to confusion.

Electrical conductivity can be expressed using a number of different units, but the typical unit is siemens per meter2 per mole (S/m2/mole) or millisiemens per centimetre (mS/cm). The mS/cm unit is generally used in Europe as a guide to the concentration of nutrients in water.

So when we talk about EC in Europe itā€™s generally accepted we are using mS/cm so therefore an EC of 2200 is so far out of the park itā€™s on itā€™s way into orbit. Iā€™m no teacher but hopefully that clears it up :thumbsup:

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#63

I think you missed my point, and no - he isnt wrong to use the numbers he is using. :slight_smile:

You are correct that a concentration of nutes that read 2200 mS (note milisiemens) would be toxic. Actually, Im not sure you could mix any nutes that read that high unless it was mud. My Apera had a max reading of 20 mS, so 2200 mS would be more than 1000 times higher concentration than the meter could even read. The scale just doesnt go that high. Thats true of any meter we would be using.

Thats why Im quite certain he was expressing his concentration in microsiemens and NOT in milisiemens, And that is perfectly ok to do.

2200 micro-siemens IS exactly the same as 2.2 mili-siemens. Those are just two different ways to say the exact same thing. Neither one is ā€œrightā€ or ā€œwrongā€.

Its like one person saying he is 72 inches tall and the other one saying, ā€œNo, you are only 6 feet tallā€. BOTH are perfectly ok.

His his meter may even be set to read in only in microsiemens. Some have that option.

So, no - he is not wrong to say his EC is 2200. At the same time, you would not be wrong to say his EC is 2.2. Both of you would be 100% correct, but both of you would be guilty of not saying what units of measurements you are using :smiley:

At the worst, he (and you at first) is guilty of not saying what units he is using - which most folks are also guilty of. People talk about PPM without ever saying if they are using the 500 or 700 scale, and EC without saying if they are using uS or mS.

On most of the forums I have read, its generally understood that if the EC number is low - under 4 say - then its mili-siemens or mS, and if its high - over say 10, then its micro-siemens or uS

Even distilled or RO water will often have a reading of a few micro-siemens, so you would never say youā€™re using 2.2 uS, because that basically nothing at all in the water. The ā€œdistilledā€ water I bought from the store reads around 20 uS, or .02 mS.

#64

By the way, CF is potentially less confusing than EC because you never have to worry about what units are being used. CF is always 10 times the EC in mS.

But, yeah, this whole subject is confusing to most people. Thats mainly because people dont bother to be clear about the units of measurement. One guy says his height is 72. But the question is - 72 what? Everyone is left to wonder if he is the new 70 foot tall man, or is he a midget at 72 cm tall or what?

So an EC of 2.2 mS = EC 2200 uS = 22 CF = PPM 1100 (500 scale) = PPM 1540 (700 scale).

All of them are perfectly good ways to say the exact same thing - which can be very confusing if you are not paying attention and/or dont say what units you are using :slight_smile:

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#65

I sometimes wonder if they deliberately make it confusing :laughing:

It does seem that (most) nutrient manufacturers nowadays use mS to express their intended EC but as you point out it is very important to know this information.

Donā€™t get me started on ppm :joy:
An EC (mS) of 1 is 500ppm according to Hanna.
According to Eutech that would be 640ppm and according to Truncheon it would be 700ppm.

Thereā€™s a difference in EC (mS) of around 0.4 between 500 and 700ppm which is by no means insignificant.

On top of this lot you have to factor in whats already in your tap water.

I find the whole thing a potential minefield and can fully understand why some just want powdered nutes and teaspoon measurements :grin:

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#66

Thatā€™s why i mentioned the copper bar in my original reply :grin:

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#67

Yeah, it sure can be confusing.

Maybe this will help with the PPM thing. PPM is just a calculated number. Its just math. No meters actually measure PPMā€™s. They measure conductivity, and then apply a multiplayer to get the PPM number. You have seen me talk about the 500 scale and 700 scale for PPM. All that means is you multiply the EC - in uS micro siemens - by .5 or .7 to get the PPM.

For example, if you have an EC of 2000 uS, or 2.0 mS, then the PPM on the 500 scale is 2000 x .5 = 1000.

For the 700 scale, the PPM is 2000 x .7 = 1400 PPM.

The same calculations using mS is 2.0 x 500 = 1000 or 2.0 x 700 = 1400.

Either way, you get the same answers.

Some meters come defaulted to the 500 scale, and some to the 700 scale. Most of the better ones allow you to choose which scale you use. The reason there are different scales is based on the type of salts in the water you are measuring.

The PPM 700 scale is based on measuring the KCl or potassium chloride content of a solution. The ppm 500 is based on measuring the NaCl or sodium chloride content of a solution and is also referred to as TDS - total dissolved solids.

Here is a link that explains it.

http://www.gyostuff.com/What_PPM_Scale_To_Use.html

There are actually are more ā€œscalesā€ than just those two. My Apera meter let me choose any number from 1 to 10.

So, its very important to know what scale your meter is reading in if your using PPMā€™s.

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#68

Good info on the PPM calculations bro :thumbsup: I always stick to EC mS and i donā€™t go far wrong. It seems to be the unit of choice in most of Europe but i see the rest of the world is using EC, CF and the various PPM scales which makes me wonder why when PPM values are based on an EC reading anyway :thinking: Iā€™ll have a read through that article when i get more time later on. A

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#69

Hello guys :blush: The Light is up and running in my new tent. Check it out :blush: plants are growing like crazy and are Very hungry. Its amazing :blush:

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