Stuppy Aquaponics Blog

Aquaponics System Response to a Restart 1/18/2017

Posted by Conor Quinlan on Jan 23, 2017 11:39:17 AM

 

 

Nitrogen (mg/L)

 

 

 

Date

pH

Total Ammonia

Ammonia

Nitrite

Nitrate

Temp (Fo)

Alkalinity

mg/L

EC (mS)

01/09/16

7.8

0.25

Neg.

~0.5

~40

76.8

55

0.73

1/11/17

7.8

0.25

Neg.

0.25

40

79.4

50

0.75

1/13/17

7.8

0.25

Neg.

0

45

76.7

50

0.77

1/16/17

7.64

0.25

Neg.

0

~50

77.8

50

.80

1/18/17

7.5

0.25

Neg

0

-

78.2

50

0.82

01/13/17  ->  Total Hardness: 195 mg/L CaCO3 equ

Calcium Level: 30-35 mg/L            Magnesium level: ~26 mg/L

Phosphate Level: ~3 mg/L (as PO4-)

 

By: Conor Quinlan

Water Quality Overview: It has been exactly one month since restarting the system and nitrification is more than significant enough to bring ammonia and nitrite levels down to well below 0.25 mg/L for the current given feeding rate of nearly 20 grams. Nitrate levels are slowly rising and should being increasing more substantially as the size of the tilapia and feeding rate increases. ph is finally beginning to fall due to the creation of H+ ions via the process of nitrification. The water is darkening due to the addition of more iron (DTPA) to bring concentrations up to 3 mg/l.  You can see the frys in the image below

Fish in fish tank 01182017.jpg

Fish Update: The blue tilapia frys have grown at a surprisingly rapid rate since their last measurement on 1/11/17.  The average weight of 10 randomly captured tilapias when weighed together totaled 79.2 grams. The average was calc. as followed: 79.2 grams/ 10 tilapia = 7.92 grams per tilapia

For the first 3 weeks the frys only increased in weight by about 1 gram. This last week however the tilapias have gained an average of nearly 4 grams. The reason behind this rapid growth is unknown it maybe a growth spurt or possibly the frys are eating more food then they previously were however the first seems more likely as I observed them feed without issue in the past. This means nutrient addition into the system will be more rapid and should stimulate effective growth soon.

The feed has been increased from 19 grams per day to the maximum the mini fish feeder can output per day which is about 43.2 grams per day, between 7-8% of the total fish body weight. Next week the mini feeder will be switch out for the regular one and the fish will be large enough to consume the 1.5mm sized fish food pellets without needing to be crushed.

Crop Update: Below is another comparison of tomato seedlings grown in the system with very low nutrient content and in the bucket testing area with high nutrient content. The tomatoes in the media bed, on the left of the image below, are exhibiting extreme nutrient deficiencies particularly phosphorous and potassium. Iron has recently been supplemented with Chelated DTPA iron to provide 3 mg/L, an adequate amount, and is beginning to improve top growth.  The one tomato on the far right is the bucket crop and is showing much better color, growth and quality.

deficient tomatoes after system start-up.jpg

A second tray of arugula was seeded on 01/09 and the first tray was therefore added to the float bed (image below). Using the staggered production method in this manner, the second tray of seedlings will be added to the float bed after 10 days on 10/19 and a third will be seeded and so on.

arugula on float rafts.jpg

The first tray of arugula, seeded on 12/30, is showing its first set of leaves but is exhibiting some slowed growth and lighter colored leaves (see image below), likely due to the low nitrate and overall nutrient content of the system. Luckily now that the tilapias are growing more rapidly and feeding rates have doubled nutrient accumulation should be more sufficient

arugula deficiency after system start-up.jpg

Bucket Testing Station: The tomatoes are growing fairly well given the air conditions which are too cold (55-64 F) for tomato growth but given the current conditions of the work area cannot be helped. Tomato #2, the hydroponic tomato, is showing very strange symptoms of a possible disease infection and may need to be removed from the testing area. The other two aquaponics tomatoes are growing very well with # 3 showing the best growth. This is interesting considering #1 was the individual that had phosphorous added. Maybe the amount was not significant enough. Despite whatever is negatively affecting the hydroponically grown tomato the upper most foliage of the aquaponics grown crops show more purpling (characteristic of a minor phosphorous deficiency) compared to that of the hydroponic crop which is much greener. I will be adding a sufficient concentration (30 mg/L) of phosphorous to bucket tomato #1, via super triple phosphate, to observe if the purpling is controlled in this manner.

The artichoke is still not showing much improvement and will therefore be moved into a hydroponic based nutrient solution with a relatively low EC (and 2.5 mS). This is because the EC of the solution in the artichoke bucket always raises overtime as if the crop isn’t up taking any nutrients. If a hydroponic solution is still unsuccessful the crop will be transplanted into a soil pot.  Below is an image of all the crops in the bucket testing area and the corresponding tomato numbers.

Bucket testing station.png

 

 

 

Topics: Aquaponics, Plants, Water, Fish