Stuppy Aquaponics Blog

System Update: Frasier, February/March

Posted by Conor Quinlan on Jul 25, 2018, 11:59:07 AM

Frasier

 

Nitrogen (mg/L)

 

 

Date

pH

Total Ammonia

Ammonia

Nitrite

Nitrate

Temp (Fo)

EC (mS)

2/12

6.4 -> 7.0

0

N/A

0

-

73.5

2.1

2/16

7.15

0

 

0

-

76.6

2.2

2/21

7.02

0

 

0

LAB TEST

74

2.3

2/27

6.7

0

 

0

-

67

2.22

3/07

6.35 -> 6.5

0

 

0

-

66

2.4

3/12

6.6 -> 6.8

0

 

0

-

69

2.4

3/21

6.6

0

 

0

-

76

2.7

3/26

6.35 -> 7.1

0

 

0

-

72

2.5

3/28

7.0

0

 

0

-

76.5

2.7

float bed-1

Above is an image of the float bed on 03/21 with leafy lettuce and iceberg lettuce dominating the area. Since the last update on 2/16 these have been our primary crops, along with red and green cabbage. The media bed has been completely cultivated with the heavy feeding greens such as Brussels Sprouts, Broccoli, and Cauliflower to determine if the fluorescent lights can provide the energy necessary to grow a harvest-able product. This was also done to determine the effects on water quality and nutrient absorption over time.

Integrated Pest Management

The Thrip population has not been a problem on either the float or media beds since their population was eradicated previously. The beneficial pesticide Botaniguard ES has been used recently to help kill any young/resistant thrip individuals that might not have been killed by Pyrethrum or Spinosad. 

Water Quality

A variety of Magnesium(Mg), Calcium(Ca), and Potassium(K) based carbonates are being incorporated into the system to measure the buffering capabilities of different mixtures as well as determine other significant influences particular combinations may have on pH and nutrient concentrations. Since K2CO3 has a less significant effect on the system’s buffering capacity on a per mass basis when compared with MgCO3 and CaCO3 it should only be used to give K levels a boost. Also CaCO3 has a very low solubility in neutral water therefore higher levels of MgCO3 are more ideal for optimal pH buffering.

Mg : Ca : K  (Ratio)  =   2 : 1 : 1

(3x) unique carbonate mixtures were required over the last 7 weeks to maintain pH and buffering capacity. Each addition measure a total of 250 grams total/addition.

The same amounts of all other, non-carbonate based, supplements were added again to maintain water quality for the next month. The latest lab sample was collected on 2/21 and indicated stable concentrations of most nutrients since adding the following supplemental compounds to the solution 2/12 and 3/12:

Super Triple Phosphate(STP): 100 grams, Chelated Iron: 75 grams, Micro Mix: 15 grams.

Below are the results of all lab tests conduct on system #1 since before and after the most recent Start-Up including the most recently test taken on 2/21. Another sample was collected 4/02 for analysis, expectations are positive

Parameters:

(Nutrients = ppm or mg/L)

(EC = mS/cm2)

Before RESET (8/22)

After START-UP 10/27

12/06

 

1/12

2/21

E.C.

1.53

0.86

1.16

1.51

2.05

Ca

64

39.06

42.31

48.97

58.62

Mg

79.5

34.19

42.84

56.76

91.23

Na

148.31

73.57

86.19

87.75

118.07

Cl

98.68

47.76

57.83

59.22

77.56

B

0.51

0.32

0.48

0.56

0.63

Fe

6.15

3.53

4.31

3.88

3.43

Mn

0.08

0.03

0.04

0.02

0

S

138.65

67.79

81.11

88.57

120.86

Cu

0.46

0.43

0.59

0.55

0.65

Zn

2.35

0.81

1.22

1.2

1.38

Mo

0.23

0

0

0.03

0.01

NO3-N

29.53

26.98

43

89.85

121.9

NH4

1.18

3.26

0.97

0.24

0.76

PO4-P

10.58

8.6

13.53

16.55

21.11

K

28.34

25.48

97.04

145.4

198.12

There have been no nutrient related incidents or issues and even with the lower levels Mn, heavier feeding crops like the Brussels sprouts and broccoli are growing without showing any signs of significant nutrient related deficiencies.

Positives:

Nitrate (NO3-) – Nitrate has reached levels more than adequate for even the heaviest feeding vegetative crops and signifies that it is time for the fish population to be thinned in order to keep nitrate levels from over accumulating and making crops overly vegetative. Symptoms of high nitrate levels  include dark green, thick, leathery leaves.

Phosphate (PO4-3) – Very important for fruiting crops but is only required in limited amounts for ideal vegetative growth. Unlike K, high PO4 concentrations can actually compete with NO3 for absorption by crops as well as promote them to flower and should be maintained <40 mg/L to maintain more aggressive vegetative growth and 20-40 mg/L for reproductive growth.

Potassium (K+) – Probably the single most important nutrient for all crops as it is required at the highest concentrations compared with any other nutrient. Even for purely vegetative growth, solutions with higher potassium produce better yields. Even more K is required for reproductive growth. K levels have increased significantly since the last test on 1/12 and would normally be considered high for vegetative growth but with the incorporation of the heavy feeders like Brussel sprouts more K can be helpful.  

There were NO significant negative water quality parameters that affected crop of fish growth/health visibly. It should be noted, however, that Mn levels are still very low and Na levels have increased significantly since the last test. Neither of these changes has prompted any negative crop or fish related issues. Mn may just have enough availability to keep crops from exhibiting any deficiency.

Fish Update

The higher temperatures have been persisting the last couple months therefore the fish feeding rate has been able to increase but at a far slower rate than anticipated by our fish feeding calculator. Even so, the results have show the fish have no problem growing to optimal size. Below is an image taken on 3/28:

fish tnak

Each fish weighed about 175 grams/fish on 2/12 and now weighs just over 325 grams/fish (weighed on 3/27), that’s a +150 grams increase in size over 7 weeks. It has been 26 weeks since the fish were only 10 grams each and the fish feed calculator indicates that they are just under their optimal size at only 10-15 grams below the target weight.

The feeding rate is considerable lower than the calculated total/day yet the weight of the fish is still almost as large as anticipated. Feeding rate is only at 350 grams/day, or 150 grams/day less than the calculated total. The fish should also be growing at a slower rate to match the lower feeding rate. This is further proof that feeding rates DO NOT need to be as large as anticipated to induce appropriate fish growth rates. In addition lower feeding rates are far more appropriate for optimal nutrient accumulation over time.  

Crop Update

The media bed is now filled to the brim with about over a dozen huge Brussels Sprouts (3x), Broccoli (5x), and Cauliflower (5x) crops all of which are growing very well. The Brussel Sprouts are just beginning to form there first harvestable leafy greens but whether or not the fluorescent grow lights can produce the amount of PAR necessary to create a viable harvest is unclear.  For this exact reason one of each heavy feeding variety was also transplanted into the LED media bed apart of system #2 in order to observe differences in overall crop growth & development at various light intensities. Below is an image of the media and float beds on 2/21 (top) and 3/21 (bottom).

media1

media2

 

 

 

 

 

 

As of 04/02 it has been just over two month since transplanting the large heavy feeding leafy greens; each is nearly 3 months old now (since first seeded).

All the newly planted crops are growing very well and only a few thrips have been spotted since the crops have matured. The beneficial pesticide BotaniGaurd ES in being used in conjunction with a bi-weekly Spinosad spray to keep any hard to kill larvae and eggs from surviving (uses the predatory fungus Beauveria Bassiana)

Topics: Aquaponics, System Maintenance, Frasier