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          PURDUE UNIVERSITY/NORTH CAROLINA STATE UNIVERSITY
              GREENHOUSE MEDIA LAB ACID ADDITION CALCULATOR
                TO CONTROL ALKALINITY IN IRRIGATION WATER
          Brian E. Whipker2, Douglas A. Bailey3, Paul V. Nelson3,
          William C. Fonteno3, and P. Allen Hammer2
          2
            Department of Horticulture, 1165 Horticulture Building,
          Purdue University, West Lafayette, IN 47907-1165
          3
            Department of Horticultural Science, North Carolina State University,
          Raleigh, NC 27695-7609
Questions or problems:
pah@hort.purdue.edu or FAX(317)494-0391 ATTN:Hammer
or Doug_Bailey@.ncsu.edu or FAX (919) 515-7747 ATTN:Bailey




ABSTRACT: Excessive alkalinity in greenhouse irrigation
water can increase substrate solution pH, resulting in
reduced micronutrient availability for plants. This
spreadsheet was designed to offer a quick and practical
method for calculating: 1) amount of nitric, phosphoric, and
sulfuric acid required to achieve an endpoint alkalinity or
pH in irrigation water; 2) the amount of nutrients added by
the acid addition; and 3) acid costs. It calculates both pH
and alkalinity after acidification, regardless of endpoint
selected. The spreadsheet accounts for the pH dependent
reaction which determines the relative percentage of each
of the carbonate species - carbonates (CO32-),
bicarbonates (HCO3-), and carbonic acid (H2CO3) - present
in the solution. In addition, the acidification calculations
accounts for the starting pH of the solution, the alkalinity
found in the initial solution, and the dissociation
characteristics of the acid selected to neutralize the
alkalinity. The spreadsheet was validated with six water
sources from Indiana and North Carolina. Those results
showed alkalinity neutralization within an acceptable range
of both target alkalinity and pH. The spreadsheet provides

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of both target alkalinity and pH. The spreadsheet provides
a chemical basis for acidification and provides results




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                      IDENTIFCATION OF SAMPLE



                                       OK



ddd            Name


               Address


               City, State,Zip


               (area code) Telephone Number


               FAX (area code) Telephone Number




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                                                        SAMPLE INFORMATION



                                                                             OK

Your Sample Information

The pH of your sample:            7.1

The alkalinity of your sample:           5.3        meq
                                                    ppm HCO3
                                                    ppm CaCO3

 Target alkalinity or pH:                1.2        pH
(pH must be below 7.2)                              meq
                                                    ppm HCO3
                                                    ppm CaCO3


   Laboratory Identification of sample




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                                                                                                     Version 3.1
                                                                                                     4/2/1996
                PURDUE UNIVERSITY/NORTH CAROLINA STATE UNIVERSITY
                   GREENHOUSE MEDIA LAB ACID ADDITION CALCULATOR



        Name: ddd                                                   Laboratory ID #:
        Street:                                                 Client ID of sample:
City/State/Zip:                                                                Date: 11-Jun-11

Phone Number:
 FAX Number:
   This spreadsheet provides the recommendations for the amount of acid to add to irrigation water in order to modify the pH and
   levels. In addition, the spreadsheet calculates the amount of added phosphorus and nitrogen that the corresponding acids wil
   plus an economic comparison of each acid.

                Your Sample Information
                            The pH of your sample:                 7.10

                         The alkalinity of your sample:             5.3

                               Target alkalinity or pH :            1.2
                                (pH must be below 7.2)
                Calculated information for your sample
                Alkalinity before acid addition
                                                   meq:            5.30
                      pH = 7.10          ppm of HCO3:             323.4
                                        ppm of CaCO3:             265.2
                Alkalinity after acid addition
                                                   meq:            1.20
                      pH = 5.74          ppm of HCO3:              73.2
                                        ppm of CaCO3:              60.1


                                                               Page 13
Alternative Acids to Add to Irrigation Water
               Acids     Phosphoric    Phosphoric   Sulfuric    Sulfuric     Nitric      Nitric
 Amounts                  Acid (75%)   Acid (85%)  Acid (35%)  Acid (93%) Acid (61.4%) Acid (67%)
For Small Volumes
ml per liter                    0.333        0.273       0.457       0.115       0.307       0.275

fl. oz. per gallon              0.043        0.035        0.058     0.015       0.039       0.035

ml per gallon                   1.260        1.034        1.730     0.434       1.162       1.042

For a 1:100 Injector
fl. oz. per gallon (conc.)       4.26         3.50         5.85      1.47        3.93        3.52

ml per gallon (conc.)          126.05       103.43       172.98     43.36      116.21      104.21

For a 1:128 Injector
fl. oz. per gallon (conc.)       5.46         4.48         7.49      1.88        5.03        4.51

ml per gallon (conc.)          161.34       132.39       221.41     55.50      148.74      133.39

For a 1:200 Injector
fl. oz. per gallon (conc.)       8.52         6.99        11.70      2.93        7.86        7.05

ml per gallon (conc.)          252.09       206.86       345.95     86.71      232.41      208.42

Nutrients Added by Each Type of Acid
       Nutrients Added: Phosphorus Phosphorus            Sulfur    Sulfur    Nitrogen    Nitrogen
  Amount Added (ppm):        124.7      124.7             66.2      66.2         57.4        57.4

Use the information above for modifying your fertility program.



                                                        Page 14
                  Cost Comparison of Each Acid Type.
                  (Average prices gives here are based on bulk purchases
                  of 5 to 15 gallons)
                   Date prices were last modified: 10/1/1995

                                                     Acid        Treatment Cost* per 1000
                      Acid           Percent     Price/Gallon    Gallons         Liters
                      Nitric          61.4          $3.00        $0.92          $0.24
                                       67           $2.70        $0.74          $0.20
                    Phosphoric         75           $6.80        $2.26          $0.60
                                       85           $8.00        $2.19          $0.58
                      Sulfuric         35           $1.90        $0.87          $0.23
                                       93           $2.95        $0.34          $0.09
                  * Reflects only treatment costs and does not include cost savings due
                  to decreased fertilizer needs associated with phosphoric and nitric
                  acids.




Notes on the use of acid to modify irrigation water pH and alkalinity.

ALWAYS ADD ACID TO WATER, NOT WATER TO ACID!

Selection of which acid type to use should be based on the nutrient program being used, type of equipment available and degre
safety desired. All acids pose a health threat if they come in contact with skin. Relatively speaking, phosphoric acid is t
followed by sulfuric,and finally nitric acid.

Use caution when working with acids. Always wear proper face, hand and body protection.

The acid must be injected with a separate injector or a twin headed injector. It should not be added to the fertilizer conce

The acids in the concentrated form can corrode metal pipes.

Retest your irrigation water (at hose end) after starting acid injection and 3-4 weeks later to confirm the adjusted pH and alka
values. Sometimes higher pH's will result in the first week of acid additions because the acids tend to dissolve the built
water deposits in pipes.




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                                                calcu


     A        B          C             D     E          F              G           H     I         J
 1                                         for calculating final based on alkalinity
 2       starting  final                                                          7.10
 3       meq       pH                                                             5.30
 4       ppm HCO3 meq                                                             5.74
 5       ppm CaCO3 ppm HCO3
 6               1 ppm CaCO3                                                    0.000
 7            5.30                 2                                            0.846
 8          323.40              1.20                                            0.154
 9          265.24             73.22                                             1.00
10            0.00             60.05                                             6.26
11            0.00              0.00
12            0.00              0.00                                             0.19        meq
13            0.00              0.00
14            0.00              0.00                                             1.20
15            0.00              0.00                                                         meq
16                              0.00
17                                                                               4.10        meq
18                              5.74
19
20                              1.20                                             7.10        meq
21                             73.22                                             5.30
22                             60.05                                             5.74
23                              0.19
24                              0.19                                            0.000
25                                                                              0.846
26                      4.098245852                                             0.154
27                      4.098245852                                              1.00
28                              0.00                                             6.26
29                              0.00
30                              0.00                                             0.19
31                      5.735774666
32                                                                               1.20
33
34
35                                                                               4.10




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       K         L           M   N   O       P
 1
 2
 3
 4
 5
 6            6.26018978                  0.0062344
 7            0.96330698                  5.2937656
 8            1.20169297                         5.3
 9            3.0589E-05
10            1.20175415
11            4.09824585                 0.00000489
12
13
14
15
16   #NAME?
17
18
19
20
21
22
23
24            6.26018978                  0.0062344
25            0.96330698                  5.2937656
26            1.20169297                         5.3
27            3.0589E-05
28            1.20175415
29            4.09824585                 0.00000489
30
31
32
33
34
35




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Notes on the use of acid to modify irrigation water pH and alkalinity.

ALWAYS ADD ACID TO WATER, NOT WATER TO ACID!

Selection of which acid type to use should be based on the nutrient program being used, type of
equipment available and degree of safety desired. All acids pose a health threat if they come in
contact with skin. Relatively speaking, phosphoric acid is the safest, followed by sulfuric,and
finally nitric acid.

Use caution when working with acids. Always wear proper face, hand and body protection.

The acid must be injected with a separate injector or a twin headed injector. It should not be added
the fertilizer concentrate.

The acids in the concentrated form can corrode metal pipes.

Retest your irrigation water (at hose end) after starting acid injection and 3-4 weeks later to confirm
the adjusted pH and alkalinity values. Sometimes higher pH's will result in the first week of acid
additions because the acids tend to dissolve the built-up hard water deposits in pipes.




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gram being used, type of
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ult in the first week of acid
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