Water Quality Parameters Quiz

Water Quality Importance

• Effective water quality testing is crucial for environmental monitoring and impacts aquatic life and ecosystems.
• Regular monitoring of water parameters is essential during aquaculture operations.

Temperature

• Affects biological activity; optimal range for growth is critical for fish health.
• Sudden temperature fluctuations can lead to high mortality in aquatic species.
• Nile tilapia thrives best at temperatures between 28-35˚C.
• Low temperatures can slow egg development, reduce growth, delay maturation, decrease food intake, and increase disease susceptibility.
• Ideal water temperature range for fish growth is generally 24-35˚C.

Hydrogen Ion Concentration (pH)

• pH measures water acidity or alkalinity, ranging from 0 (very acidic) to 14 (very alkaline).
• Neutral pH is 7; values below indicate acidity, while above indicates alkalinity.
• pH significantly influences fish production; desirable range for fish culture is 6.5 to 9.
• Extreme pH levels can lead to fish mortality and reproduction issues:
  • pH 4: Acid death point
  • pH 4-5: No reproduction
  • pH < 6.5: Slow growth
  • pH 11: Alkaline death point

Dissolved Oxygen

• Oxygen is essential for all fish species for growth and survival.
• Comfortable dissolved oxygen levels are around 3 ppm with ideal levels at 5 ppm.
• Insufficient oxygen leads to poor growth and increased disease outbreaks.

Salinity

• Measures the amount of salt in water, expressed in parts per thousand (ppt).
• Can be assessed using a hydrometer (simple and inexpensive) or a refractometer (more accurate).

Water Turbidity

• Defines the clarity of water and is impacted by suspended particles.
• Higher turbidity can inhibit light penetration, affecting plant growth and nutrient levels.
• Types of turbidity include mineral (causes brown or reddish water), which can prevent fertilizer efficiency and plankton growth.
• Plankton turbidity arises from high phytoplankton and zooplankton concentrations, causing various shades of water.
• Transparency measured using a Secchi disk; ideal depth for productive ponds is between 10-30 cm.

Total Hardness

• Measures the concentration of calcium and magnesium ions in water.
• Hardness affects the pH of water, typically maintained between 50 and 300 ppm for optimal fish growth.
• Total hardness determined using ethylene diamine tetraacetic acid (EDTA).

Transparency

• Indicates the depth of light penetration into water.

Ammonia

• Results from decomposing organic materials; poses a significant water quality issue at high biomass levels.
• Exists in equilibrium as NH3 (toxic) and NH4+ (non-toxic), dependent on pH and temperature.

Water Depth

• Optimal depth for fish culture is around 1 meter; traditional milkfish ponds function well at depths of 40-60 cm.

Instruments and Measurements

• Instruments used for monitoring water quality parameters include:
  • Meter Stick: Water Depth (cm, m, ft)
  • Thermometer: Temperature (°C, °F)
  • Secchi Disc: Transparency/Turbidity (cm, m, ft)
  • D.O. Meter: Dissolved Oxygen (ppm)
  • Refractometer: Salinity (ppt)
  • pH Meter: pH level
  • Total Hardness Test Kit: Total Hardness (ppm)
  • Ammonia Tester Kit: Ammonia (ppm)