Stuppy Aquaponics Blog

Nile System update 10/12/17

Posted by Conor Quinlan on Oct 12, 2017 1:30:00 PM

System #2

 

Nitrogen (mg/L)

 

 

 

Date

pH

Total Ammonia

Ammonia

Nitrite

Nitrate

Temp (Fo)

Alkalinity

mg/L

EC (mS)

9/15

6.87

0

N/a

0.25

250-300

78

-

1.1

9/18

6.83

0

 

0.25

250

 

35

1.17

9/20

6.75

0

 

0.25

-

 

-

1.16

9/22

6.9

0

 

0.25

-

 

-

1.10

9/25

6.94

0

 

2

250

 

50

1.10

10/4

7.2

0

 

0.5

200

 

-

1.12

10/6

7.3

0

 

0

-

 

90-100

1.11

10/9

7.35

0

 

0

150

 

-

1.16

            9/15 -> 9/26 -> 10/4 -> 10/10 : Total Hardness: 400 -> 360 -> 350 -> 360 mg/L CaCO3 equ
Calcium Level: 48 -> 45 -> 40 -> 43.2 mg/L    Magnesium level: ~ 68.3 -> 60.3 -> 60.9 -> 61.5 mg/L
P (PO4-) = 0 -> 15 -> 15 mg/L

 

peppers.jpg

Water Quality Overview

All fruiting crops are producing with success,  with the majority of current issues related to lack of adequate PAR lighting in our warehouse environment. Vegetative growth is slightly more prominent but not significant enough to affect the fruit development of the various crops. 

No carbonate additions have been required over the past month. The likely cause is that the crops are having an effect on pH. This has not affected the production of fruiting crops within the system and they appear to be receiving enough nutrients over time. A water quality test is being conducted to determine how the K, P and Mn levels have been affected over the last month.

STP (super triple phosphate) as well and MnSO4 and chelated iron have been added maintain limited nutrient levels.  

The efficiency of the clarifier was recently tested by determining the total water volume dumped from the media bed into the sump bed. The more waste build up in the media bed that had occurred over time the greater the loss of water volume and therefore the lower the change in water height in the sump after a given media siphoning period.

I determined that 4.125” increase in water height in the sump was the maximum drainage that could occur from the media bed. After a 4-month period the test was repeated and it was discovered that the drainage decreased to 3.5” (or a 0.625” drop; 15.15% decrease in water volume), not too bad considering the buildup of root material that is also taking up considerable space.

 

Fish Overview

Unfortunately, the fish feeding trial will need to be redone as the feeder reset itself without notice. Overall the new catfish skretting feed appears to provide the best results with the lowest level of floating waste. The aquamax feed appeared to have considerably higher floating waste levels. The skretting feed will be re-tested first followed by the aquamax.

The fish have grown well and are averaging 625 grams/tilapia (nearly 1.4 lbs) as of 10/10, which is a reasonable 80-gram increase in size since the last weighing on 9/18. It has been 6-months since their introduction at 15 grams/fish meaning the tilapia are still well beyond their anticipated harvesting cycle.

fish_1.jpgfish_2.jpg

Above is a comparison of the change in size of the tilapia over the course of the last two weeks with the first image image being from 9/18 and the second from 10/10.

We are still maintaining double what the tilapia should be weighing at this point in the grow cycle despite a constant 300 g/day feeding rate. This is proof that tilapia have a very flexible feeding requirement that can be manipulated to help the crops

 

Crop Overview

Most of the fruiting crops including the tomatoes and cucumbers placed in the system are nearing the end of their growth cycle. All crops produced viable fruit,  with the LED producing much larger tomatoes and cucumbers overall. The fluorescents have no problem growing peppers of multiple varieties. 

The cucumbers and leafy greens have been removed from the media bed in order to make room for four new tomato varieties. These will be tested in the media bed under the LED fixtures this time. The same pepper individuals will be used to compare yields of LED vs Fluorescents. Below are images showing the change to the media bed.

media_bed_1.jpgmedia_bed_2.jpg

Below are images of the float beds with each of the different artificial light sources (LED bottom). Each float bed now contains swiss chard and basil seedlings for a final comparison between LED and Fluorescents. The chard and basil will also be added to the hydro NFT system as well for comparison. The tomato seedlings are currently growing out in the LED float bed and will be transplanted to the media soon.

float_bed_1.jpgfloat_bed_2.jpg

Topics: Aquaponics, Niles, LED