IJA-2018v8n19 - page 8

International Journal of Aquaculture, 2018, Vol.8, No.19, 145-150
147
1 Methodology
Tanks for indoor and outdoor freshwater were constructed from fiberglass, each filled with 55 L (approximately
15 gallon) water and located in UCSI University. For outdoor freshwater tank with plants, 14 days basil seedlings
(30 seedling for each tanks) were located on the filtration system to form a hydroponic or aquaponic system,
respectively. All tanks were uniformly aerated and were filled with freshwater every 7 day after water samples
were collected. Phosphates, ammonia and chlorine were determined following the methodology listed below.
Water samples were collected from indoor and outdoor tanks, respectively in a duration of 4 sampling (one per
week, a total of 4 weeks) between April and May 2018. The water temperature of indoor tanks is 21°C-32°C
while the water temperature of outdoor tanks is 24°C-35°C. The quantity of feed given to a tank each day based
on the total weight of fishes. The feeding rate is fixed to be 2.5% per day. pH for all the tanks were standardized at
pH 7 and were recorded using LAQUA Twin pH meter.
Colorimetric analysis is measured by the Lovibond Tintometer. The method involves the matching of the color of
light transmitted through a specified depth of sample with color transmitted from the same source through a set of
colored glass slides.
1.1 Phosphates
Two 13.5 mm/10 mL molded cells were filled with water samples to the 10 mL mark. One of the molded cells
was place in the left hand compartment of the comparator. One Lovibond Phosphate HR Tablet was added into
another molded cell and it was crushed and mixed to dissolve. The molded cell was left to stand for 10 minutes
and placed in the right hand compartment of the Lovibond tintometer with standard comparator discs 3/136. The
comparator was held against a standard light source (not fluorescent) and the color produced was match against
the disc by rotating the disc until a color match obtained. Phosphate concentration (mg/L) was displayed in the
bottom right aperture of the comparator.
1.2 Ammonia
A total of 10 mL of water samples was poured into each 13.5 mm/10 mL molded cells. One cell was placed in the
left hand side of the Lovibond tintometer with standard comparator disc 3/125. One Lovibond Ammonia No.1
tablet and one Lovibond Ammonia No.2 tablet were added into another cell. The tablets were crushed and mixed
until fully dissolved. The cell was placed in the right hand side of the comparator and allowed to stand for 10
minutes. After 10 minutes, the color produced was match against the standards by holding the comparator against
a light source of white light. The disc was rotated until the nearest color match was found, the ammonia
concentration (mg/L) was displayed in the indicator window.
1.3 Chlorine
One 40 mm/20 mL molded cell containing the sample was placed in the left hand compartment of the Lovibond
tintometer with standard comparator disc 3/2APH. Another 40 mm/20 mL cell was rinsed out with sample and
filled to the 20 mL mark. One Chlorine HR tablet was added into the cell. It was crushed with a clean stirring rod
and mixed thoroughly until dissolved. One acidifying GP tablet was added into the cell, crushed and mixed
thoroughly until dissolved. The cell was placed in the right hand compartment of the comparator and the
comparator was held facing a standard white light source. The disc was rotated until the nearest color match was
obtained. The concentration of total chlorine (mg/L) was displayed at the bottom right hand aperture of the
comparator.
2 Results
The concentration of phosphate, ammonia and chlorine from different water sample sources with different
conditions, outdoor tank, indoor tank and planted tanks were recorded and tabulated in Table 1.
3 Discussion
Based on the results, the phosphate concentration in both indoor (4.0 ±0.5 mg/L) and outdoor fish tanks (4.0 ±0.5
mg/L) has higher concentration compared to planted tank (0 mg/L) (Table 1). This is due to the uneaten fish feeds,
faeces, dead matter or the water itself in the tanks contribute in the increasing of phosphate level. Therefore,
1,2,3,4,5,6,7 9,10,11,12
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