Curious Whats Everyone Ppm At During Veg & Flower In (r)dwc

[hiiipower]

Hey @Junk, how much air do you pump into your res? Do you know how much lpm/g? How many air stones:water? Just wondering, cause your plants look nice even though that's quite a high ppm.

 

[mojavegreen]

Early veg: 250 ppm,5.9 ph, temp 66
Late veg: 450 ppm, 5.9 ph, temp 66

Early flower: 400 ppm, 6.0 ph, temp 66
Late flower: 650 ppm, 6.0 ph, temp 66

That's about where I'm at as well.

 

[Jay786]

Im GH, which is the 500 scale with RO water (although I don't see them give a different scale if you are not)

I know it's high. It's really high...but these plants smash it.

View attachment 536921

Jh

Im GH, which is the 500 scale with RO water (although I don't see them give a different scale if you are not)

I know it's high. It's really high...but these plants smash it.

View attachment 536921

How many weeks in flower are these?

 

[jackwhite]

the moment ive gone over 900ppm My plants get nute burn. im guessing it also has to do with the type of nutes you use for your grow. im currently using technaflora and i havnt been able to go up to 1000ppm. the happiest they been was b/w 700ppm-875ppm. I started at 25% nute strength and work my way up to 60% nute strength

 

[WS4U]

Veg 250-400 flower 500-800.... Dwc over 3 years and ran all kinds of numbers, less is more imo. One love

 

[Buzzz]

There is technically 3 different ones (I think) but one of them is not used a lot. Australia or Euro I believe.

& because this is America, & we can't measure anything the same way as the rest of the world. Even if their system is better/easier. We are the Imperialists! lol

But seriously, I work on cars a lot. & at least for that, I love metric. Standard sucks.

I guess I gotta go back to school for growing collards...

 

[organix4207]

Plants only use what they can , just because you pour more nutes on them doesn't equate to higher yields .
I'm on the 500 scale
250 ppm - 2 week old seeds & rooted cuts
400-650 - veg
650-1100- flower
All these #'s are strain dependent and I use tap water with ppm of 115.

 

[Junk]

I have no idea why they use two scales for PPM's... But the good news is, that they only use one scale for EC... And they all mean exactly the same thing.
1 EC equals 500 PPM on the 500 scale, and that equals 700 ppm on the 700 scale.

They use two scales (3 actually) because ppm meters are typically just EC meters. & some nute bases use materials that are the same PPM, but are more, or less, electrically conductive per PPM. So a different correction factor is applied. The EC meter needs to know what the multiplication factor is - to give you ppm.

But EC is not the "end all, be all" of measurements. As I just explained, different types of salts can have different conductivity. PPM is also an easier number, mentally, to adjust your nutes on. It's just easier to wrap your head around.

All these people throwing up replies and not telling what scale they are using. Wow

I don't think you understand how it works. Aside from that, ppm is what the OP asked for, ppm during veg & flower.

It doesn't matter what scale people are on. It doesn't matter that the scale changes depending on the nute line. So long as everyone has calibrated their TDS meters correctly. TDS meters are simply EC meters that multiply by a factor to give you PPM. PPM is an easier denominator to work with small numbers.

So, I'm on the 500 scale, others can be on the 700 scale. So long as their meters know that, we can talk in PPM & all be talking about the same thing (roughly). It doesn't matter that the scales change, so long as you are using the proper correction factor for your nutes, & we are using the proper correction factor for our nutes, PPM is now the same (in theory).

It doesn't matter what scale people are using, or the fact that it changes for some people. Everyone (pretty much) is using an EC meter that converts to TDS, which is given as a PPM measurement. So long as they have the correct multiplier for their nute line, we are talking about the same thing. After your meter does it's thing & gives you a PPM reading, we now have a common denominator. The fact that EC is a hard, constant, reading, doesn't make it inherently superior for our purposes. I don't find it to be easier to measure.

ppm scale changes depending on were you live.

It's based on the nute line, & what they have used for their base, not where you live. Because of different national laws & regulations, there is often a location correlation, but it's not the the inherent cause.

Hey @Junk, how much air do you pump into your res? Do you know how much lpm/g? How many air stones:water? Just wondering, cause your plants look nice even though that's quite a high ppm.

Sorry I missed this bud. Sometimes I have like 22 alerts & I forget some of them.

For the rez, I have one of these (Eco Plus 5)
https://www.hydroponics.net/i/132951

I split it & run two of these (Eco Plus Aqua lung x 2)
https://www.hydroponics.net/i/140866

Then I have one of these (Eco Plus 7)
https://www.hydroponics.net/i/136485

That powers the air stones that are in all the buckets, including the control bucket. 17 buckets in all, excluding the rez. So each bucket has it's own air stone powered by the EP7. The res has two aqua lungs powered by the EP5. I don't have any test results to prove it, but I have yet to see a setup that did not benefit from more/better aeration.

There are 4 main reasons I'm able to feed at such a high ppm. 1. I am pumping the entire setup so full of oxygen that the plants can metabolize a lot. 2. Right now I'm giving the space 100w of light per ft^2. 3. I supplement Co2 4. I use Botanicaire Liquid Karma. I don't work for Botanicaire, or associated with them in any way. But that Liquid Karma stuff, is liquid gold. I don't know what it does, or how it does it, but you can slam the plants with higher nute levels, & they take it. If I removed the LK from the recipe, I would have to drop the nute levels a bit.

People who say the plants can only use a certain amount of nutes are 100% correct. But you can force the plant to need/use more nutes. More light, more Co2, more oxygen. My environment is on steroids, which is why I'm able to give the plants steroid level nutes. I've gone as high as 2k ppm (my meter just reads "----")

When people say the plant can only use so much...While that is true, it's an oversimplification. Most nutes are correlated. In order to uptake one nutrient most efficiently, it has to uptake another nutrient, which is related to another etc.

A very simple example of what I mean is the Liquid Karma. I would burn my plants at the levels I use without it. But if I add it, they take it & explode with growth. & they are using most of it, some days they drink 25 gallons in 24 hours.

Jh

How many weeks in flower are these?

That picture I showed was about 5 weeks. Here is one of my current plants at 4 weeks. Steadily taking 1600 ppm with every feed/water.

Plants only use what they can , just because you pour more nutes on them doesn't equate to higher yields . All these #'s are strain dependent and I use tap water with ppm of 115.

Indeed, but we raise that threshold with other means like I expressed above. I wasn't picking on you when I said that....yours just happened to be the next quote in the series. But I agree with you, that you can't just dump more nutes in & expect performance to increase.

 

[hiiipower]

That's really interesting @Junk. Better late than never, thanks that's great info!

 

[Junk]

My point was, it's useless to tell your PPM's unless you also list what scale and base water reading.

I tend to type a lot. I have a lot of information stored in the brain & I type fast. So, a lot of the time, I'm not very clear. Also, to be clear, I'm not looking to be confrontational or disagreeable with you. I just disagree with you, & here is why....(& if I'm wrong, show me where, I'm reasonable)

A point I was trying to make is that it's not useless. The scale isn't needed.

If we are trying to compare weight...& I give you a weight in pounds, say 10# & you have a weight in kilos, say 5kg. If you multiply your weight by 2.2, the figure is now in pounds...I'm at 10, you are 11, both in pounds. It doesn't matter what we started at, all that matters is that we have a common denominator.

We are now talking about the same thing. All that other info is useless.

To get onto the ppm platform, that's all that is happening. But instead of one weight conversion (kg to #) we are talking about a few...say "stone" to #. Or pick another one. But if we all convert to #, we are all talking about the same thing.

That's precisely what the meter is doing, albeit not 100% precisely (almost no meter does). But we are talking parts per millionth. So, if I'm at 1000 ppm, technically what it's saying is 1,000/1,000,000, or 1/1,000th. or .001. EC would read 2. Some people argue that because EC is universal, it's a better measurement. But let's look at it. & this is really the only time we need to talk about scales. So that would be an EC of 2. because I'm on the 500 scale.

Pretend I messed up & I should be on the 700 scale. My EC still reads 2. PPM though, should be 1,400/1,000,000 or 1.4/1,000 or .0014. So, the PPM is higher, but the same EC?

So can you explain to me how the EC is the better measurement? EC is reading the exact same? But PPM has changed?

I understand how the lack of conversion can make it seem like it's a "truer" measurement. But it doesn't account for the fact that different materials have differing EC's. So, if I use a nute solution that has very low EC per ppm, your EC is misleading you...

That is why the scales are there. It's a correction factor & it is used in MANY types of measurements. I have different mics to measure room acoustics. Each one has a different correction value applied.

I could just go by the decibel rating. It's universal? But it would be inaccurate for the true purpose.

You are essentially saying "you need to tell us what math you used to get there." You don't. It doesn't matter anymore....so long as the math is correct, we are talking about the same thing.

My point was, it's useless to tell your PPM's unless you also list what scale and base water reading. Cheers

No, it isn't. PPM is PPM, & even with inaccuracies or as a meter ages, it's still a pretty tight measurement. You have an EC pen that is also a calculator to give you PPM. You are saying you want to check the match and convert it back to EC? The whole reason a correction factor is applied is because EC can be misleading, not PPM. (maybe I'm crazy?) But I showed you in the example above, EC will read the same, but PPM is different. Why is EC the measurement you want to go by?

You are essentially saying, I want to go by a measurement that has no correction factor applied....& I don't get that.

Electrical Conductivity can be fooled...that's why the scales (correction factors) are applied.

I agree with you on the base water reading. That would be useful to know up front.

I hope that doesn't sound confrontational. I'm not arguing with YOU per se, I'm arguing it in my head...& have been doing so for quite a while...& the above is the conclusion I continuously arrive at. So, if I'm wrong, help me see the light.

People talk about EC, like it's THE gold standard of measurement. I don't know why you think that. It has a decimal place of 1, & it is NOT the same for all substances, that's why it has correction factors.

& the argument is that it's somehow better, uncorrected?

 

[Junk]

I thought of a good way to sum it up...

I hear people saying that we should just use EC...because it doesn't change. But PPM's do...so EC is the better measurement.

That's completely backwards. The EC is being tricked into reading the same. The PPM's are changing ...appropriately. That's why the scales exist. To correct EC.

So how people have landed on the idea that it's better, in almost ANY way, I don't get.

 

[ken dog]

I thought of a good way to sum it up...

I hear people saying that we should just use EC...because it doesn't change. But PPM's do...so EC is the better measurement.

That's completely backwards. The EC is being tricked into reading the same. The PPM's are changing ...appropriately. That's why the scales exist. To correct EC.

So how people have landed on the idea that it's better, in almost ANY way, I don't get.

For example,

If I'm on vacation and I asked you to dose my system to 1400 ppm while I'm away, how would you do that?

To dose my system, you must first know what scale I am referring to. Otherwise, you could dose it too high or too low.

So again, ask yourself this question... If I needed you to come by my house and dose my system at 1400 ppm, what scale would you use?... or would you just prefer me to tell you what EC I would like you to dose it to?

 

[Junk]

That's the dumbest argument I've heard yet.

Is that what we are talking about? Ease of having someone else cover your system? If someone were to come here, they would use my meter which measures the EC & puts it into ppm. So, I would just tell them ppm.

Apparently that explains something meaningful?

Let m.

Why are you measuring EC....can you tell me? Do you care how about the potential electric conductivity?

The plant doesn't give a !@#$ about the electrical conductivity you are giving it. It cares about the periodic table of elements & environtment.

If all you care about is EC, I can make you a salt solution to the perfect EC & save you a ton of dough. We'll both get rich.


EC, is simply the means that we use, to measure something. Because it's easy, it's cheap, it's inexpensive. But that is not what we are after. What we would like to know, is the ratio of water to _______. That is not what EC is for. But we CAN use it to figure that out...if we apply the scale.

The only time the scale becomes involved is when you are measuring EC & you want to make that number represent something meaningful. That's that the TDS meter does.

We don't care about the electrical conductivity. We care about how much of a substance is in the solution. Different elements on the periodic table of elements have different EC values. Giving me a sum total of the EC tells me nothing. I have to multiply the scale to get that number.

All I'm saying is what I hear sometimes being presented as "the holy grail" of measurements doesn't make sense to me.

You are measuring EC, but it can be misleading. That's why the scales exist. The EC simply tells you electrical conductivity. Different things have different levels of EC, so a correction factor is applied.

Maybe you can arrive at what I'm saying this way... If I give you the just the EC, why can't you tell me the PPM?

Why can there be a large difference in actual content per /m3 (ppm) but the EC will read the same?

Now, explain to me how the measurement platform that will account for those differences that the EC does not catch... is not better?

Measure how you want, measure by color if you want to, I don't care... But either answer those questions or maybe let's stop saying that EC is the golden measurement. I've read in a few places, people discouraging ppm, because EC is constant. I've thought about it,...& I'm pretty sure, you have it bass ackwards. The Mrf is telling you that their solution is more/less electrically conductive per PPM, thus the scales. Their solution is taking up MORE volume, but reads the same electric conductivity. So, how is it PPM that is the problem?

You cannot accurately measure content with EC, the way you can with PPM, I don't how much simpler I can make it. Think about why the scale is there.

You are using EC to try to divine how much of a product is in the solution, to a level that is more accurate than PPM. It isn't possible. It is EC that fluctuates. PPM does not (speaking relatively) Get it?

 

[ken dog]

Simply put, PPM can mean two different measurements, depending on which scale you use.
EC means one thing... It's universal.

 

[ken dog]

By the way, if a person prefers to use PPM's, I would strongly suggest to use the 700 scale... That way you will never overdo it when converting from EC.

 

[Junk]

EC means one thing... It's universal.

No, it's not....Not in the way that matters. & there it is again...that's what I'm talking about, "it's universal." It's a faulty measurement for what we want.

The logic you are using is that a pound is a pound. Everywhere all over, a pound is a pound. So we should use that.

But you can't tell me how many people are on a plane by knowing the weight. Because people weigh different amounts! They do not all have the same value in pounds....

Now, if I tell you, the average weight, of the person (the mf'ing scales) you can do it....get it?

Just as not all people have the same value in pounds, not all chemicals have the same value in EC. Claiming the reading is universal, doesn't change the fact that it's a less accurate way to do it, considering the company has told you how their solutions EC correlates to PPM.

It's singular value in being universal would be if every ppm had an = EC value. But they do not. The mechanics of how it does the test is irrelevant. As a test for actual content per m3, it can be, & is, fooled.

 

[ken dog]

Let's say they tell you to put in 1000 ppm... So you put in a thousand ppm on the 700 scale, and it reads 1.4 EC.

Now, let's say you use the 500 scale instead, and you put a thousand PPMs in... You end up with 2.0 EC...much too high.

See the inaccuracies associated with using PPM's?... It is much more accurate to specify EC. Then the user can decide which scale they want to use, and adjust accordingly.

 

[jumpincactus]

Nutrient Strength: EC, PPMs and TDS Explained

When we feed a nutrient solution to our plants, one of the most critical factors to get right is the nutrient strength. But there seems to be a whole lot of confusion lingering around how to measure the strength of your nutrient solution-especially among beginners.

The two major measurements in use today are:

EC - Electrical Conductivity

TDS - Total Dissolved Solids

EC
Let's start with the obvious: the more mineral-based nutrients you add to some water, the more concentrated the solution becomes. Pure water does not conduct electricity, but the more mineral ions we add, the more readily it will conduct. Therefore, the electrical conductivity (EC) of your nutrient solution is a fairly reliable measure of how much nutrient is dissolved in it overall.

To measure conductivity we can use an EC meter, also known as a conductivity meter. It has two electrodes that, when dipped in the solution, measure its electrical charge by passing a small charge between them.

It's important to measure the conductivity of your source water (before you have added any nutrients or other additive products) - this not only gives you the "baseline" measurement so you have an idea of the purity of your source water, but it also gives you an idea of what "room" there is left for additional nutrients.

If EC is Electrical Conductivity, what units is this measured in?

You may have heard growers say things like "When my plants are in full flower I feed them up to EC 2.2" - but 2.2 what?

The answer is Siemens, or more accurately, millisiemens. (One millisiemen is one thousandth of a Siemen.)

There's no need to get your head twisted over this. Siemens are to "electrical conductivity" what feet, yards, meters or inches are to "length" - it's simply the unit of electrical conductance.

The important thing to get straight is that EC refers to the scale (also known as the 'parameter') and siemens are the units on this scale. EC is the most widely accepted measurement for the strength of nutrient solutions, and is the standard in Europe and many other parts of the world. The one notable exception is North America which, for some reason, prefers to use the rather cumbersome and vague alternative: TDS.

TDS
TDS stands for Total Dissolved Solids-it quantifies the concentration of dissolved solids contained in a solution. Proponents of TDS argue that it's a more suitable parameter than EC for measuring nutrient concentration, since it measures by quantity or weight rather through the implication of electrical conductivity.

The problem with TDS measurements are they are great in theory, but fairly absurd in practice. The only way of accurately measuring the TDS of a nutrient solution is to evaporate all the liquid and measure the residue-this would kind of defeat the point!

What is TDS measured in?

Remember, like "EC" - TDS is a scale, or a parameter, just like length, temperature and volume. The unit of TDS is ppm (parts per million.) A TDS reading of 60 ppm means there are 60 milligrams of dissolved solids in each liter of water, or 60 mg/l.

So do TDS Meters work in a different way to EC meters?

No.
TDS meters work in actually the same was as EC meters! Both measure the electrical conductivity of the nutrient solution they are dipped in. The difference lies in how the information is displayed to you.
A TDS meter measures the electrical conductivity in exactly the same was as an EC meter, but it simply uses an in-built conversion factor to display the strength of the nutrient solution in ppms.

It's these "conversion factors" that form the proverbial can of worms. They can vary significantly from meter to meter.

Conversion Factors
TDS NaCl

NaCl is a conversion factor based on Sodium Chloride (regular table salt.)
The conversion factor range is 0.47 to 0.5.
Non-linear meters based on NaCl typically use: 0.5 x the EC level (if converting from µS to ppm or mS to ppt) or 500 x the EC level, if converting from mS to ppm.
TDS 442™

442™ or Natural Water™ is a proprietary scale based on properties of naturally occurring fresh water. The 442™ part is an abbreviation of 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride.
The conversion factor range is 0.65 to 0.85.
Non-linear meters based on 442™ typically use: 0.7 x the EC level (if converting from µS to ppm or mS to ppt) or 700 x the EC level, if converting from mS to ppm.

TDS KCl

KCl is a conversion factor based on Potassium Chloride.
The conversion factor range is 0.5 to 0.57.
Non-linear meters based on KCl typically use: 0.55 x the EC level if converting from µS to ppm or mS to ppt) or 700 x the EC level, if converting from mS to ppm.

TDS 640

A less popular conversion factor.
The conversion factor range is 0.64 to 0.67.
Non-linear meters based on 640 typically use: 0.64 x the EC level if converting from µS to ppm or mS to ppt) or 640 x the EC level, if converting from mS to ppm.

Yes, four different possible conversion factors means that four different meters that give measurements in ppm may all give different readings from the same solution! However, all EC meters should give the same reading in the same solution as there's no conversion factor necessary.
I know, I know … TDS sounds like a confusing thing - but it's really just a measure of the total ions in solution. For every gallon of water you have X mg's of stuff in it. If one of your friends starts talking about their nutrient solution in terms of TDS, be sure to find out what scale they are using. Many growers, especially in Europe, in an effort to avoid confusion, use EC. If you are still confused, contact the manufacturer of your nutrients and find out what they recommend. Remember to ask them what TDS scale they use if they give you dosages in terms of ppm.
Likewise, if you are working with a TDS meter that only has a ppm display, remember you need to be sure of the conversion factor being used. TDS comes into its own when you need to measure individual elements in applications such as nutrient and water quality, tissue analysis results and soil analysis. Results from these laboratory tests will give individual elemental readings in ppm or mg/l. Remember, a TDS meter will only give you an approximation of the overall nutrient concentration, based on the conversation factor used.
Below is a table to show the relationship between the various methods of displaying the strength of a nutrient solution.

EC (mS)

EC (µS)

TDS NaCl

(EC µS x 0.5)

TDS KCI

(EC µS x 0.55)

TDS 640

(EC µS x 0.64)

Natural Water™ 442

(EC µS x 0.7)

0.6

600

300

330

384

420

1.2

1,200

600

660

768

840

1.8

1,800

900

990

1,152

1,260

2.4

2,400

1,200

1,320

1,536

1,680

3.0

3,000

1,500

1,650

1,920

2,100

Jargon Buster

EC= Electrical Conductivity

TDS= Total Dissolved Solids

PPM= Parts Per Million
PPT = Parts Per Thousand

µS (or µS/cm)= micro-Siemens (one millionth of a siemen.)

mS (or mS/cm)= milli-Siemens (one thousandth of a siemen.)

NaCl= Sodium Chloride (EC-to-TDS conversion - EC x 0.5)

KCl= Potassium Chloride (EC-to-TDS conversion EC x 0.55)

442= 442 Natural Water™ (EC-to-TDS EC x 0.7) (The "442" is an abbreviation for 40% sodium sulfate, 40% sodium bicarbonate and 20% sodium chloride.)

Making Sense of your Meter

Here are some popular TDS meters along with their conversion factors, where applicable.

MAKE & MODEL

TDS FACTOR

BLUELAB



TRUNCHEON

Displays EC and both NaCL (0.5) and 442™ (0.7)

GUARDIAN

Displays EC and both NaCL (0.5) and 442™ (0.7)

HANNA



HI 98300

0.65

HI 98301 / 98302

NaCL (0.5)

GRO-CHECK COMBO



HI 981404N / HI 981405N

442™ (0.7)

HI 983301N

442™ (0.7)

HI 983301N/5

NaCL (0.5)

HM DIGITAL



TDS-3

NaCL (0.5)

AP-2

None - just measures EC

COM-100

Displays EC and TDS (user can select NaCl, 442 or KCl factors)

OAKTON



EcoTestr, TDSTestr11, PTTestr35

User Adjustable TDS Factor between 0.4 and 1.0



Default setting: 0.71

MILWAUKEE



MW401, MW402

NaCL (0.5)

T75, T76

NaCL (0.5)

C65, C66, MW301, MW302

None - just measures EC

MW801

NaCL (0.5)

MW802

0.65

NUTRIDIP



Tri-Meter 202

NaCL (0.5)

Tri-Meter 203

442™ (0.7)

Handheld

442™ (0.7)

 

[MGRox]

@Junk Apples and oranges.

Parts Per Million (PPM) - is commonly used as a measure of small levels of pollutants in air, water, body fluids, etc.
Parts per million is the mass ratio between the pollutant component and the solution and ppm is defined as
ppm = 1,000,000 mc / ms (1)
where
(mc = mass of component (kg, lbm)
ms = mass of solution (kg, lbm))
http://www.engineeringtoolbox.com/ppm-d_1039.html

--In our cases of adding dry salts to water; this means 1 mg per liter = 1 ppm and yes this is constant.

However;
Electrical Conductivity (EC) - is the measure of a material's ability to accommodate the transport of an electric charge.

-All "Salts" will increase conductivity but not necessarily to the same degree; relative to "weight" as above.

here's a chart of electrical conductivity for elements

Electrical conductivity is important as plants uptake Ions and these ions have charges. Movement through osmosis from low to high concentrations is related to this electrical conductivity. So, typical EC ranges that are used for plant A or B are more related to soil conductivity vs root (internal and external surface) conductivity.

Lol timing @jumpincactus

 

[Junk]

This is getting monotonous. ALL "home use" PPM meters read "EC", with the exemptions for meters like, "Hanna's Colourimeters", that won't work for our uses in growing, because of the discoloured water. That's it. From there, the chip within these PPM meters, calculate PPM by, first measuring EC, then multiply that by the predetermined algorithm you have it set for. It internally translates from EC to PPM's,

I have said that...at least 4x. Almost verbatim. It's a an EC meter, with a calculator in it, that multiplies by a correction factor.

If any of you are debating which test is more accurate...can you tell me why..there is a "correction factor" involved?

The correction factor isn't changing the EC (because after all that's absolute (roll eyes) it's changing the ppm, which is the only damn thing you care about. You could give a dogs nuts how EC the water is.

Talking about PPM's leaves room for errors when doing this,.

No, it doesn't. That's what I've been trying to explain to you.

The EC is what is being measured incorrectly. Hence the manufacturer telling you, "Hey, our substance will still measure 1 EC, but it's got 400 more ppm. It will measure the same EC value, but it has more parts per million. & just to correct the statement above PPM can be applied to anything measurable. all it is is parts per/_cubed.