How to convert NPK to PPM?

[Snype]

Been trying to see exactly what PPM of every element that I'm using to try and figure out some things. I've read some very confusing things about how to calculate this and I see a lot of debate over it. I basically use:

6 mL General Hydroponic FloraMicro (5-0-1)
9 mL General Hydroponic FloraBloom (0-5-4)

I use these rates per gallon and my water is 140 PPM from the tap. When I mix up a gallon with my formula, it reads 740 PPM. So when I subtract my water, I would get 600 PPM. Now I need to know how much of each element in PPM that I'm getting. I know in reality I need to know the weight of each element but I would think I would get a decent estimate with this equation by just estimating every mL to be a gram
(even though it is not always the case):

1 Gal of Solvent (Tap Water) = 3.79 Kg
6 mL of GH FloraMicro = 6 g
9 mL of GH FloraBloom = 9 g
1 g = 1,000 mg

To find the PPMs for FloraMicro:
To find PPM of N:
{6g (6mL of Micro) x 0.05 (5% N) x 1,000 (mg)} / 3.79 Kg (1 Gal)

N = 79.2 PPM
Ca = 79.2 PPM
K = 15.8 PPM
B = 0.2 PPM
Cu = 0.2 PPM
Co = 0.01 PPM
Fe = 1.6 PPM
Mn = 1 PPM
Zn = 0.24 PPM
Mo = 0.013 PPM

Total FloraMicro = 177.5 PPM

Now when I do the same thing with the FloraBloom and put 9 g into the equation for 9 mL Bloom per Gallon, I get:

P = 119 PPM
K = 95 PPM
Mg = 36 PPM
S = 24 PPM

When I combine all of these totals, I get 452 PPM and then when I add my 140 PPM water, I get roughly 600 PPM. Is there a better equation that I can use so that I can find where my loss of 140 PPM went? Seems like I'm doing something wrong.

 

[Snype]

Someone must know something?

 

[smailer]

Hello Snype,
So sorry for my English, it's not my native language, and I hope you can understand me
first of all I will operate on metric units.
And looks like you forgot use some conversion factor for the elements usually all elements in nutes like some oxides or salts. and to calculate pure value of elements you need to use it.

for example P on nutrients usually puts like P2O5 and conversion factor is 0,436 for this element.
And for your FloraBloom (you use 9g per gall, for me it's equal to using 2,77g/l)

P value is 68,4777 mg\l --- usually this is the same to 68,48ppm
for TDS with converson factor 0,5
-----------
Calculation For the FloraBloom i use following content: (you can have different numbers on your label than me)

-----------
Result: in mg/l (same to ppm) for 9g per gallon or 2,77g\l
N= 0
P= 68,4777
K= 101,1604
Ca= 0,1981
Mg= 55,1202
S= 61,7932
and Cl=24,65
and if you summing up Total: 312,33mg\l (ppm)

But you must take in mid what it's amount of pure elements.
and in total PPM rate of your nutrient solution you will see bigger amount on TDS meter screen, because another parts of salt from each nutrient consist we don't count. also we don't count some buffers what GH use.

Anyway for have approx. calculation total EC of your nutrient solution this method is suitable.

oh.. yes and small table of conversion factors of elements.

I hope I was useful

 

[Snow Crash]

Hey Snype. Your math looks good to me. The reason for the difference is that what is labeled on the bottle is only the guaranteed minimum. There will always be more in there than what they say.

Electrical Conductivity readings, and ppm conversions, are also not reliable as perfectly accurate. Maybe you're ppm readings would be more consistent with your calculations if you were using a different conversion factor, maybe 0.44, 0.5, or 0.7... I dunno, but you cannot really compare them.

The thing to do is calculate your levels and measure the EC. Keep good records and try to watch the plant closely. After a few grows you'll see when to boost what, or what EC level works best and when. These are relational tools, not CSI lab equipment.

 

[mowood3479]

snype, I do not know the answer, but I would LOVE to figure it out... I remember reading something relevant in the jacks/peters thread mayb in the coco section? some guys were posting the ppm of each element at various dosage rates and incorporating their tap water.. i suck with the search function but mayb if ur good at it u can find it? I think itd be worth reading... i may go look for it to re read...

 

[rives]

Snype, have you tried the Cannastats calculator? If you go to the download page, you can get the full calculator along with a bunch of preloaded nutrient information and the ability to compare/contrast 7 different nutrients, or just use the simpler version that is live on the net.

Net version, bottom of the page - http://www.angelfire.com/cantina/fourtwenty/articles/profiles.htm

Download page for the full calculator, it's the top download - http://www.angelfire.com/cantina/fourtwenty/articles/download.htm

 

[Snype]

Snype, have you tried the Cannastats calculator? If you go to the download page, you can get the full calculator along with a bunch of preloaded nutrient information and the ability to compare/contrast 7 different nutrients, or just use the simpler version that is live on the net.

Net version, bottom of the page - http://www.angelfire.com/cantina/fourtwenty/articles/profiles.htm

Download page for the full calculator, it's the top download - http://www.angelfire.com/cantina/fourtwenty/articles/download.htm

I downloaded it but I don't have the right program so it takes out some parts of it. I have no idea. Anyway, instead of using 1mL=1g in my equation above, I will add in the weights of the liquids according to Lucas or pH.

General Hydroponic FloraMicro: 1mL = 1.22691292875989g; 1 Gal=4644.37g=4.644Kg

General Hydroponic FloraBloom: 1mL = 1.14894117150396g; 1 Gal=4349.21g=4.349KG

1 Gal = 3785.41mL

Think I'm getting closer. We shall see.

If anyone can please tell me what the PPM of each element is in 6mL Micro / 9 mL Bloom per gallon, i'd love to hear.

 

[reg24]

@6ml/gal
N 97
P 0
K 16
Mg 0
Ca 97
S 0
Fe 1.9

That was micro from shroomys thread times .6
Same thing for bloom times .9

...reg

 

[Snype]

To find the PPMs for FloraMicro:
To find PPM of N:
{7.36g (6mL of Micro) x 0.05 (5% N) x 1,000 (mg)} / 4.644 Kg (1 Gal)

N = 79.2 PPM
Ca = 79.2 PPM
K = 15.8 PPM
B = 0.2 PPM
Cu = 0.2 PPM
Co = 0.01 PPM
Fe = 1.6 PPM
Mn = 1 PPM
Zn = 0.24 PPM
Mo = 0.013 PPM

Total FloraMicro = 177.5 PPM

I'm still coming up with the same numbers when I put in the total weight. Somehow I think I need to calculate the weight of each element or compound. Man this is confusing. Can anyone shed more light on this or what the equation is. I don't care for programs, just want the equations instead.

@6ml/gal
N 97
P 0
K 16
Mg 0
Ca 97
S 0
Fe 1.9

That was micro from shroomys thread times .6
Same thing for bloom times .9

...reg

Can you link me to that thread please?

 

[Snype]

Hello Snype,
So sorry for my English, it's not my native language, and I hope you can understand me
first of all I will operate on metric units.
And looks like you forgot use some conversion factor for the elements usually all elements in nutes like some oxides or salts. and to calculate pure value of elements you need to use it.

for example P on nutrients usually puts like P2O5 and conversion factor is 0,436 for this element.
And for your FloraBloom (you use 9g per gall, for me it's equal to using 2,77g/l)

P value is 68,4777 mg\l --- usually this is the same to 68,48ppm
for TDS with converson factor 0,5
-----------
Calculation For the FloraBloom i use following content: (you can have different numbers on your label than me)
View Image
-----------
Result: in mg/l (same to ppm) for 9g per gallon or 2,77g\l
N= 0
P= 68,4777
K= 101,1604
Ca= 0,1981
Mg= 55,1202
S= 61,7932
and Cl=24,65
and if you summing up Total: 312,33mg\l (ppm)

But you must take in mid what it's amount of pure elements.
and in total PPM rate of your nutrient solution you will see bigger amount on TDS meter screen, because another parts of salt from each nutrient consist we don't count. also we don't count some buffers what GH use.

Anyway for have approx. calculation total EC of your nutrient solution this method is suitable.

oh.. yes and small table of conversion factors of elements.
View Image


I hope I was useful

This is starting to hurt my head. I'm sure something useful is in your post. Thanks!

 

[rives]

Snype, you should be able to use the online version, I think. Anyhow, these were the results that I got for 6(M)+9(G)ml/gln -

N - 97.2 Total (91.4 Nitrate, 5.8 Ammonium)
P - 59.6
K - 106.8
Mg - 41.0
S - 27.3
Ca - 97.2
Fe - 1.94491
B - 0
Mn - .97245
Zn - 0
Mo - .01556
Na - 0
Cu - 0
Cl - 0
Co - .00972
Si - 0
Se - 0

Edit - holler if you want them broken out separately. You need to get the calculator working - the damn thing is incredible for this, and they have a bunch of nutrients and additives already in the data base.

 

[Snype]

Snype, you should be able to use the online version, I think. Anyhow, these were the results that I got for 6(M)+9(G)ml/gln -

N - 97.2 Total (91.4 Nitrate, 5.8 Ammonium)
P - 59.6
K - 106.8
Mg - 41.0
S - 27.3
Ca - 97.2
Fe - 1.94491
B - 0
Mn - .97245
Zn - 0
Mo - .01556
Na - 0
Cu - 0
Cl - 0
Co - .00972
Si - 0
Se - 0

Edit - holler if you want them broken out separately. You need to get the calculator working - the damn thing is incredible for this, and they have a bunch of nutrients and additives already in the data base.

I found your link to the online version! Thanks so much! Now one last question that you may or may not know. I also need the individual PPMs for Kool Bloom Powder at the rate of 1.25 grams per Gallon. I think that powders are done differently than liquids but you seem like you know more than me on the subject. Here's the Guaranteed Analysis of KBP:

Total Nitrogen... 2%
(2% Ammoniacal Nitrogen)

Available Phosphate (P2O5)... 45%

Soluble Potash (K2O)... 28%

Magnesium... 1%

Sulfer... 1.5%

Derived from: Ammonium Phosphate, Ammonium Sulfate, Magnesium Sulfate, Potassium Phosphate, Potassium Sulfate.

 

[rives]

Yes, the calculator is intended for liquid nutrients because of the potential discrepancy in converting between volume and weight. If I recall correctly, the swing can be around 10%.

Anyhow, this is what I got when I plugged in 1.25ml/gln of KoolBloom.
N - 6.6 (Ammonium)
P - 64.8
K - 76.8
Mg - 3.3
S - 5.0

 

[HatchBrew]

Why?

 

[Snype]

Yes, the calculator is intended for liquid nutrients because of the potential discrepancy in converting between volume and weight. If I recall correctly, the swing can be around 10%.

Anyhow, this is what I got when I plugged in 1.25ml/gln of KoolBloom.
N - 6.6 (Ammonium)
P - 64.8
K - 76.8
Mg - 3.3
S - 5.0

So when I add up everything from:
6mL Micro
9mL Bloom
1.25g PKB

From what you state, I get:

N - 103.8 Total (91.4 Nitrate, 12.4 Ammonium)
P - 124.4
K - 183.6
Mg - 44.3
S - 32.3
Ca - 97.2
Fe - 1.94491
B - 0
Mn - .97245
Zn - 0
Mo - .01556
Na - 0
Cu - 0
Cl - 0
Co - .00972
Si - 0
Se - 0

So do you think that because you entered a powder into your calculator that my numbers will be correct above or do I need to somehow figure out a powder formula for the PKB? So if you are right, then the above PPMS are correct. If anyone can find any problems, please let me know. I'm still missing some PPM's from Boron and Zinc and whatever else.

 

[rives]

So do you think that because you entered a powder into your calculator that my numbers will be correct above or do I need to somehow figure out a powder formula for the PKB? So if you are right, then the above PPMS are correct. If anyone can find any problems, please let me know. I'm still missing some PPM's from Boron and Zinc and whatever else.

I think that it is probably close enough to get a good idea of what is going on. Remember, with the goofy fucking labeling laws for nutrients, the "guaranteed analysis" doesn't necessarily reflect what is really in the mix - it just establishes a minimum of what MUST be in the mix. So, the levels can be higher than stated and still be in compliance, and there can be unlabeled ingredients included that don't have to be listed. Strange way of doing things.

The missing elements such as Boron, Zinc, etc. are not listed on GH Micro's guaranteed analysis, so there is no way to determine if or how much is present.

 

[Snype]

I think that it is probably close enough to get a good idea of what is going on. Remember, with the goofy fucking labeling laws for nutrients, the "guaranteed analysis" doesn't necessarily reflect what is really in the mix - it just establishes a minimum of what MUST be in the mix. So, the levels can be higher than stated and still be in compliance, and there can be unlabeled ingredients included that don't have to be listed. Strange way of doing things.

The missing elements such as Boron, Zinc, etc. are not listed on GH Micro's guaranteed analysis, so there is no way to determine if or how much is present.

Thanks for the help! Trying to figure out these formulas and make whatever changes that I need to with some testing. This is going to come in handy.

 

[holystomata]

First thank you to the work and ref. charts posted above. Super helpful in getting me to this stage.

I think I’ve got it but I would like some feedback to see if I have this correct. I haven’t been able to follow the calculations to do on my own so far. it’s easier for me to spell it out as an equation and helpful because I want to create a spreadsheet for myself. I know there is one at canna stats but you cannot see the formulas and I also want to lay mine out in a different way; week by week so I can see the progression.

The important thing for me was to realize that PPM is another way of notating mg/l. So in the end you end up finding the weight of a particular ion in 1 liter of water.

So to spell out the formula step-by-step using K for Pro-Tekt as an example:

1. Find the (VMD) volumetric mass density (p=m/v) of the product found on the label. Convert to g and ml. m=mass, v=volume

Pro-Tekt is 4.1 Kg per 1 liter. It’s best at this point to convert to g and ml so: p = 4100 g / 3785 ml = 1.0832 g/ml.

2. Convert nutrient dose from per gallon to per liter (d) ; divide per gallon dose by 3.785.

Pro-Tekt 1.3 ml per gallon is now 0.3435 ml per liter.

3. Find the weight of your dose. multiply volume of dose by VMD (p). The answer will be in grams; it’s best at this point to convert to mg.

p = (0.34 ml x 1.08g/ml) x 1000 = 372.04 mg.

4. Multiply by guaranteed analysis percentage (g). K rating for Pro-Tekt is 3.

372.04 mg x 0.03 = 11.16 mg. This is the weight of K20.

5. Multiply weight of K20 by modifier (m), in this case 0.83, to get the weight of K ions.

11.16 mg x 0.83 = 9.26 mg

Now we know we are adding 9.26 mg per liter of water. mg/l is the same as PPM.

PPM = (p)(d)(g)(m)

(4100 g / 3785 ml)((0.3435 ml x 1.0832 g/ml) 1000)(0.03)(0.83) =
(1.0832 g/ml)(372.04 mg)(.03)(.83) =
9.26 PPM K for 1.3 ml Pro-Tekt in 1 gallon of water.

NOTE: A spreadsheet does not round up so doing this by hand or calculator it is important to carry (p) and (d) out to 4 places after the decimal point.

Anyone find any issues with this? Any feedback would be helpful.

 

[holystomata]

Too advanced for everyone?