What is pH?
Measure hydrogen ion in water or soil.
What is the ideal pH for fish?
6.5 - 8.5
THREE (3) ways to manage high pH.
Acid, aerations, prepare pond early, add alum, add organic matter
Does alkalinity same as water hardness?
No. Alkalinity is base, water hardness is metal ions/salts in water.
What happen to fish when DO > 5 mg/L?
Grow well
What happens to fish when DO < 2 mg/L?
Die
Daily pH fluctuation - sunrise
Photosynthesis increase, carbon dioxide reduce, pH increase
Give FOUR (4) ways how LOW temperature affect fish metabolic and physiology?
Stop eating/eat less, reduced growth, delay/prevent maturation & spawning, slow down egg development, increase infections and diseases
Daily fluctuation of pH - Late evening
Respiration increase, photosynthesis reduce, carbon dioxide reduce, pH reduced
What is alkalinity?
Total amount of base present in water, prevent large pH change.
TWO (2) ways to overcome low pH.
Lime, alkaline fertilizer
Daily fluctuation of oxygen - NIGHT
Respiration, reduced DO, photosynthesis stop.
Give TWO (2) signs of low DO.
Stop eating, eat less, come to surface, tadpoles at the margin of pond, water snails, odour of rotten egg.
Daily fluctuation of oxygen - DAYTIME
Higher photosynthesis, higher DO, higher phytoplankton
Which one better? High alkalinity or low alkalinity? Reason.
High alkalinity. Prevent drastic pH change.
List THREE (3) factors for the oxygen requirement of the fish.
Fish species, fish size, water temperature, physiological
Give THREE (3) factors that affects oxygen solubility.
Temperature, atmospheric pressure, salinity
Give THREE (3) ways how HIGH temperature affects the fish?
Increase growth, increase food requirements, stimulate fish gonad maturation & spawning, increase oxygen demand