Can Bacillus and Photosynthetic Bacteria Be Used Together?

Smart Water Exchange Tips for Hot Seasons in Aquaculture

As aquaculture continues to grow rapidly, the industry faces three pressing challenges: environmental deterioration, frequent disease outbreaks, and residual drugs in aquatic products. The use of probiotic bacteria in water bodies has emerged as an effective way to tackle these issues. These beneficial microbes not only help decompose excess nutrients and reduce COD, but also balance the micro-ecosystem by competing with pathogenic bacteria—ultimately reducing disease occurrence.

There’s a well-known saying in aquaculture:

“Low-yield ponds grow algae, high-yield ponds grow bacteria.”
This reflects the importance of using microbial preparations wisely for better outcomes with less effort.

Can Bacillus and Photosynthetic Bacteria Be Used Together?

This is a common question among aquaculture farmers. To answer it, we first need to understand how Bacillus and Photosynthetic Bacteria (PSB) behave.

🌱 Bacillus

• Main function: Breaks down large organic molecules in water.
• Bacillus exists as spore-forming dormant cells. To activate them, we typically mix with molasses and provide aeration.
• Optimal activity pH: 6.0–7.0.
• If the pH rises above 7, its activity declines significantly.

☀️ Photosynthetic Bacteria (PSB)

• Thrive in alkaline environments with pH 9.0–9.5.
• If active PSB is mixed with just-awakened Bacillus (which prefers a lower pH), the Bacillus may return to dormancy or even become ineffective.
• When Bacillus undergoes this kind of "double dormancy and reactivation," it loses effectiveness—like an army weakened before battle.

❌ Conclusion: Do NOT use Bacillus and PSB at the same time.

✅ Correct Usage Method:

Day 1 Morning:

• Use Bacillus to decompose large organic matter.
• Ensure proper aeration or use oxygen tablets for best results.

Day 2:

• Apply Photosynthetic Bacteria to break down smaller organic compounds and further purify the water.
• Think of Bacillus as the "first wave of attack" and PSB as the "cleanup crew."

💧 Scientific Water Exchange During High Temperatures

As we enter late May, high temperatures across the country bring water quality challenges such as reddish or blackened water, excess ammonia/nitrite, and cyanobacteria outbreaks. Water exchange is one of the most cost-effective ways to improve water quality—but it must be done properly.

Here’s a step-by-step guide to scientific water exchange:

1. ⏰ Time It Right

• Add new water every 7 days, adjusting based on:
  • Temperature
  • Water condition
  • Weather (e.g. shorten interval during heatwaves or rainy seasons)

2. 🌄 Add Water in the Early Morning

• At night, photosynthesis stops but respiration continues, especially between 3–5 a.m., when oxygen is lowest.
• Injecting water in the early morning helps raise oxygen levels quickly.

3. 🚿 Use Clean, Oxygen-Rich Water

• Water should be pollution-free and well-oxygenated.
• Maintain safe temperature differences:
  • <2°C for nursery ponds
  • <5°C for larger ponds
• Use surface water (insert pipe ~30cm below surface).
• Before adding new water, drain old bottom water.
• Use fine mesh nets at inlets to prevent wild fish/shrimp from entering.

4. 📏 Control Water Volume

• Too little water = ineffective exchange.
• Too much = loss of plankton, affecting pond ecology.
• Ideal exchange: 20–30 cm depth each time.
• In case of oxygen depletion or water deterioration:
  • First remove 1/3 to 1/2 of the old water
  • Then refill with new water

5. 🌿 Re-Fertilize After Water Change

• New water can dilute pond fertility.
• Apply fertilizer to promote phytoplankton growth.
• Aim for water transparency of about 30cm.

📌 Summary

• Do not combine Bacillus and PSB in one application. Use them on separate days to maximize efficiency.
• During hot weather, follow timely, appropriate water exchange protocols to maintain pond health.
• Always monitor pH, oxygen, and temperature before introducing any treatment or new water.

By understanding microbial interactions and adopting smarter water exchange strategies, farmers can reduce costs, prevent disease, and boost aquaculture productivity sustainably.

🌐 Stay tuned for more aquaculture insights. Share this post if you found it helpful!