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How to Use Aquaculture Disinfectants Correctly: Complete Guide
2026-04-23
LIUHE
Accurate calculation of chemical dosage is the core of ensuring efficacy, avoiding phytotoxicity, and preventing and controlling diseases in aquaculture. Insufficient dosage fails to achieve bactericidal, anthelmintic and water regulation effects, while excessive dosage may cause poisoning of farmed aquatic products, imbalance of aquatic microecology, and even chemical residue problems.
Therefore, accurate dosage calculation is crucial. Here is an introduction on how to calculate the appropriate dosage scientifically.
Step 1: Measuring the Pond Water Volume
Accurate measurement of aquaculture water body is the foundation of aquaculture chemical application, which directly determines the dosage accuracy of disinfection and water regulation agents. It mainly consists of three steps: area measurement, water depth measurement and volume calculation, with specific methods as follows:
1. Area Measurement
Rectangular Ponds Area = Length (m) × Width (m)
Circular Ponds Area = 3.14 × Radius² (m) (Radius = Diameter ÷ 2)
Trapezoidal Ponds Area = [(Top Width + Bottom Width) ÷ 2] × Height (m)
Irregular Ponds Adopt the division method: divide the pond into several triangles, measure the three side lengths of each triangle respectively, and calculate the area of a single triangle using Heron's formula:
Area (㎡) = √[l(l-a)(l-b)(l-c)]
l = (a+b+c)/2 (Semi-perimeter, m)
a, b, c: Three side lengths of the triangle (m)
Area (㎡) = √[l(l-a)(l-b)(l-c)]
l = (a+b+c)/2 (Semi-perimeter, m)
a, b, c: Three side lengths of the triangle (m)
2. Water Depth Measurement
Arrange two measuring lines crisscross at the midpoint of the fish pond. Start from 1 meter off the bank along each line, measure the water depth at 1-meter intervals until 1 meter from the opposite bank. Sum up the water depth of all measuring points and divide by the total number of measuring points to get the average water depth of the pond.
Special Note: When disinfecting large aquaculture water bodies such as reservoirs and lakes with chemicals, if the water depth exceeds 2m, the chemical application volume shall be calculated based on a unified water depth of 2m to avoid insufficient chemical concentration in the upper layer or chemical waste in the lower layer due to excessive water depth.
Special Note: When disinfecting large aquaculture water bodies such as reservoirs and lakes with chemicals, if the water depth exceeds 2m, the chemical application volume shall be calculated based on a unified water depth of 2m to avoid insufficient chemical concentration in the upper layer or chemical waste in the lower layer due to excessive water depth.
Useful Tip: Simplified Depth Monitoring
After measuring the pond water depth, mark the position close to the water surface on fixed markers (like feeding platforms) and record it as h0. When water depth changes (rainfall, drainage, etc.), simply measure the distance between current surface and mark (h1):
- If surface is below mark: Current depth = h0 − h1
- If surface is above mark: Current depth = h0 + h1
3. Total Water Volume
Total Water Volume (m³) = Area (㎡) × Average Water Depth (m)
Step 2: Calculation of Dosage for Sprinkling Chemicals
Multiply the obtained volume of the water body by the concentration of the applied chemical to get the dosage. The calculation formula is as follows:
Total Dosage (g/mL) = Total Water Volume (m³) × Recommended Concentration (ppm/g/m³)
Note: 1ppm = 1g/m³ = 1mg/L
Total Dosage (g/mL) = Total Water Volume (m³) × Recommended Concentration (ppm/g/m³)
Note: 1ppm = 1g/m³ = 1mg/L
Step 3: Safety Guidelines for Chemical Application
To ensure the safety of your aquatic stock and the personnel handling the chemicals, please adhere to these professional standards:
- Read the manual carefully before use. Strictly follow the usage and dosage in the manual according to the requirements of different farmed aquatic products, and pay attention to all precautions.
- For whole pond sprinkling disinfection, add a sufficient amount of clean water to the container first, then put in the disinfectant and dissolve it fully, and sprinkle it evenly after complete dissolution. It is recommended to stand against the wind during operation and apply the medicine from the leeward side of the pond; the best time for medicine application is 9:00-15:00 on a sunny day.
- Avoid direct contact with the liquid medicine during operation; for highly irritating disinfectants (such as chlorine-containing preparations), do not work for a long time in a high-temperature environment. When the temperature exceeds 32℃, the single chemical application time should not exceed 2 hours.
- For large ponds with water depth exceeding 2 meters, the interval zonal disinfection method can be adopted: apply the medicine twice, with half the total dosage each time for half the water surface, and the interval between the two applications should be no less than 4 hours.
- Patrol the pond in time to observe after chemical application, and handle abnormalities immediately; do not use disinfectants when the water is anoxic or the weather changes suddenly (such as rainstorm and strong wind).
Quick Reference: Common Fishery Chemicals
| Chemical Name | Primary Application | Recommended Dosage | Withdrawal Period (d) |
|---|---|---|---|
|
Calcium Oxide (Quicklime) |
Pond clearing |
Clearing: 200–250 mg/L Disinfection: 20 mg/L |
0 |
|
Bleaching Powder |
Bacterial disease prevention |
Clearing: 20 mg/L Disinfection: 1.0–1.5 mg/L |
≥ 5 |
| Bacterial disease prevention |
Disinfection: 0.06-0.1mg/L (depending on the species of fish and shrimp) |
≥ 10 | |
| Pond clearing/prevention |
Clearing: 5-6mg/L (depending on the species of fish and shrimp) Disinfection:0.2mg/L-0.3mg/L (depending on the species of fish and shrimp) |
≥ 10 |