01/05/2025
Thanks to .brasil for explaining the importance of monitoring pH in your reef tank.
Why monitor pH in marine aquariums?
A drop in pH in a reef tank can be a sign of several potential problems. Keeping the pH stable is essential for the health of corals, fish and invertebrates. Below are some problems that can arise with a drop in pH:
1. Stress and death of marine organisms
• Corals and invertebrates are very sensitive to pH. Drops below ~7.8 can cause stress, polyp closure, bleaching and even death.
• Fish also suffer, presenting accelerated breathing, abnormal behavior and low immunity.
2. Reduction in calcification
• Reef-building corals (such as SPS and LPS) depend on a high pH (ideally between 8.1 and 8.4) to form calcium carbonate. With low pH, the formation of coral skeletons is impaired, leading to slow growth or regression.
3. Increased dissolved CO₂
• A low pH usually indicates excess CO₂ in the water, often due to poor ventilation or overcrowding. This also reduces oxygenation, affecting all aerobic organisms in the system.
4. Problems with alkalinity (KH)
• A drop in pH may be related to low alkalinity, which is the natural pH buffer. This leads to an unstable system, where the pH varies rapidly (pH oscillation), which is dangerous for corals.
