mg/L IS ppm...
this is from here:
I started this thread because I see an increasing number of people looking to improve their grows by trying a new nutrient line or product when in fact there is little to no correlation between plant health and any one product or line. Instead, there is a direct correlation between the nutrient profile you develop with your line and the health of the plants being profiled.
I will however deal with nutrient profiles and their application more in depth in another thread that covers whole nutrient lines. The basis of this thread will be understanding N-P-K guaranteed total analysis, actual available ppm analysis, and how to apply that understanding to a variety of bloom boosters on the market.
First, let me start by saying ppm meters do not measure parts per million. Ppm meters measure Electric conductivity which is then converted (different meters convert at different rates) into a “ppm figure.” As if the conversion factor was not inaccurate enough, meters measure total EC. This means along with the elements available for plant up-take the meter is also reading dissolved solids that are dyes, preservatives, fillers, or anything else that happens to be in the solution. For these reasons meters contain an inherently unacceptable level of error for the use of nutrient profiles and we must turn to math for these purposes.
Developing nutrient profiles from scratch begins with the guaranteed total analysis or the N-P-K listed on each nutrient label. By law the numbers listed for N-P-K are listed in percents and are a percentage of the total amount of nutrient. For example 0-50-30 means the nutrient contains 0% total N, 50% total P, and 30% total K. These numbers however are often misleading because total N, total P and total K is not the same as available N, available P and available k.
Now, plants are only able to uptake elements that are both 1) inorganic, and 2) in their most simple ionic form. In the case of N, P, and K those forms are NO3, and NH4 (N); HPO4 (P); and K+ (K). So, before Guaranteed total analysis can be converted into an actual available ppm analysis you must identify the forms of N-P-K that are provided and the percentage at which they oxidize into forms that are usable by the plants.
In the case of the boosters in question N is provided as NO3 and no conversion is necessary. P is converted from P2O5 at a rate of 43.6% useable (HPO4) P. And K is converted from K2O at a rate of 83% useable (K+) K.
Now that we have our oxidization rates we can begin with solutions. Because ml/mg per liter is already in ppm the starting point is there. 1g per liter means 1000 ppm have been added to solution. So, divide the 1000 ppm by the N-P-K ratios to find the guaranteed total ppm. Then, total ppms are divided by available forms of the element. Then the actual available ppm is divided by 3.785 to arrive at the actual available ppm analysis for 1g per gallon of each booster.
Here is the math:
Guaranteed Total analysis:
Guaranteed Total analysis: Open sesame
N 5
P 45
K 19
Guaranteed Total analysis: Beastie bloomz
N 0
P 50
K 30
Guaranteed Total analysis: Cha-Ching
N 9
P 50
K 10
Guaranteed Total analysis:
Moab
N 0
P 50
K 30
Garanteed Total analysis:
Shooting Powder
N 0
P 9
K 20
mg/ml per liter is ppm:
1g/liter total ppm: Open sesame
N 50
P 450
K 190
1g/liter total ppm: Beastie bloomz
N 0
P 500
K 300
1g/liter total ppm: Cha-Ching
N 90
P 500
K 100
1g/liter total ppm:
Moab
N 0
P 500
K 300
1g/liter total ppm:
Shooting Powder
N 0
P 90
K 200
In these cases N-P-K are provided as N: (NO3) P: (P2O5) K: (K2O). However plants can only uptake elements in their most simple (inorganic) ionic form. So N is up takable in the forms of NO3 and NH4, P in the form of HPO4 and K in the form of K+. In the case of P, 43.6% of P2O5 oxidizes into usable HPO4. In the case of K, 83% of the K2O becomes the usable form K+.
Actual Available ppm:
1g/liter actual available ppm: Open sesame
N 50 X 1 = 50
P 450 X .436 = 196.2
K 190 X.83 = 157.7
1g/liter actual available ppm: Beastie bloomz
N 0
P 500 X .436 = 218
K 300 X.83 = 249
1g/liter actual available ppm: Cha-Ching
N 90 X 1 = 90
P 500 X .436 = 218
K 100 X .83 = 83
1g/liter actual available ppm:
Moab
N 0
P 500 X .436 = 218
K 300 X.83 = 249
1g/liter actual available ppm:
Shooting Powder
N 0
P 90 X .436 = 39.24
K 200 X .83 = 166
And from 1 liter to 1 gallon: (/3.785)
1g/gal actual available ppm: Open sesame
N 50 X 1 = 50 =13.21
P 450 X .436 = 196.2 = 51.84
K 190 X.83 = 157.7 = 41.66
1g/liter actual available ppm: Beastie bloomz
N 0 = 0
P 500 X .436 = 218 = 56.8
K 300 X.83 = 249 = 65.78
1g/liter actual available ppm: Cha-Ching
N 90 X 1 = 90 = 23.78
P 500 X .436 = 218 = 57.60
K 100 X .83 = 83 = 21.93
1g/liter actual available ppm:
Moab
N 0 = 0
P 500 X .436 = 218 = 56.8
K 300 X.83 = 249 = 65.78
1g/liter actual available ppm:
Shooting Powder
N 0
P 90 X .436 = 39.24 = 10.37
K 200 X .83 = 166 = 43.86
So, 1 gram per gallon of these products yields the following actual available ppm nutrient profiles:
Final Actual available ppm analysis (1g per gallon):
Open sesame:
N 13.21
P 51.84
K 41.66
Beastie bloomz:
N 0
P 56.8
K 65.78
Cha-Ching:
N 23.78
P 57.60
K 21.93
Moab:
N 0
P 56.8
K 65.78
Shooting Powder:
N 0
P 10.37
K 43.86
