Reducing Aggression in the Cichlid Aquarium

Note on the table: The original values from the Tallings’ paper, which have been posted on this page since 1997, are shown in lightface. Joe Gargas, former Director of Research and Development for the Wardley Corporation and an expert in water chemistry and treatment, corresponded with me in April 2009 and has generously calculated the updated values in boldface in the table. These represent conversions of the Tallings’ data to, in some cases, more modern units of measurement now in widespread use and more familiar to aquarists.

 

 

Water Chemistry of the AfricanGreat Lakes

  Chemical Constituent L. Victoria L. Malawi L. Tanganyika
  Electrical conductivity
(µmho = microsiemens)

91-145

210-220

606-620

  Total solids
(mg/L)

76-118

460

  Total solids
(mg/L) average

58.24–118.0

134.4–140.0

387.84–460.0

  Sum of cations
(meq/L)

1.04-1.21

2.45

7.30-7.46

  Sum of anions
(meq/L)

1.08-1.77

2.5-2.59

7.25-7.71

  Total hardness as
calcium carbonate
CaCO3 (mg/L)

19.12-70.83

60.58-85.60

186.33-224.0

  Total calcium as
calcium carbonate
CaCO3 (mg/L)

12.50-37.50

41.0-49.0

23.0-44.0

  Total magnesium as
calcium carbonate
CaCO3 (mg/L)

6.625-33.33

19.58-36.60

163.33-180.0

  pH

8.0-8.8

8.5-8.6

8.66-9.06*

  Na (sodium)
(mg/L)

10.4-13.5

21.0

57-63.6

  K (potassium)
(mg/L)

3.7-4.2

6.4

18.0-35.5

  Ca (calcium)
(mg/L)

5-15

16.4-20.7

9.2-17.6

  Mg (magnesium)
(mg/L)

1.59-8

4.7-8.8

39.2-43.3

  Alkalinity as
calcium carbonate
CaCO3 (mg/L)

12.5-76.5

118.0-129.0

301.0-340.5

  HCO3 + CO3 (bicarbonate,
carbonate) (meq/L)

0.25-1.53

2.36-2.58

6.02-6.81

  Alkalinity as
HCO3 + CO3 (bicarbonate,
carbonate ions) (mg/L)

7.62-46.66

71.98-78.69

183.61-207.7

  Cl (chloride)
(mg/L)

3.9-7.0

3.57-4.3

20.9-36.6

  SO4 (sulfate) (mg/L)
(using ion-exchange resins)

2.3

5.5

7.2-15.3

  SiO2 (dissolved silica)
(mg/L)

3-20

1.1-4

0.3-6.6

  NO3 · N (nitrate-nitrogen)
(µg/L)

11-29

below detection
limit

  PO4 · P (phosphate)
(µg/L)

3-13

<7-30

7

  Total P (phosphorus)
(µg/L)

47-67

[21 (doubtful)]

 

 

The values tabulated here were extracted from Technical Document TD/46 written by Plisnier et al. (1996) of LTR (Research for the Management of the Fisheries of Lake Tanganyika). These pH values were measured on pelagic waters (near-surface and at various depths) every 1-2 weeks for 1 year using the same pH meter and standardized sampling methods

 

Lake Tanganyika: pH Measurements, 8/93-7/94

  Depth and
Sampling Station
Mean ± SD Median No. of Samples
  Surface      
  Bujumbura(north end)

9.01 ± 0.23

9.03

29

  Kigoma (east coast)

9.06 ± 0.13

9.06

30

  Mpulungu (south end)

9.02 ± 0.15

9.02

32

  100 meters      
  Bujumbura(north end)

8.66 ± 0.21

8.68

30

  Kigoma (east coast)

8.79 ± 0.13

8.77

29

  Mpulungu (south end)

8.86 ± 0.12

8.90

31

 

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