Intensive water re-use systems and well-boats, commonly used in aquaculture, are particularly susceptible to CO₂ and total dissolved gas buildup. Monitoring CO₂ and TDG levels in these systems and during transport is crucial for ensuring the health and well-being of fish and shellfish. More commonly measured parameters that include oxygen, pH, and ammonia, can at best, provide only an estimate of dissolved CO₂ levels.

Fish

Elevated CO₂ levels lead to slower growth in fish, reduced feed conversion efficiencies and increased susceptibility to diseases such as nephrocalcinosis. Elevated TDG can be caused by pump leaks, over supersaturation of oxygen or other gases from source water, or temperature changes, and can lead to gas bubble trauma that may cause fish mortality.

Continuous in situ monitoring of key water quality parameters including CO₂ and TDG reduces the burden of manual testing, maximizes the efficiency of degassing systems and water pumps, and allows for prompt alerts to allow correction of adverse conditions.

Shellfish

Increased CO₂ levels cause a shift in the carbonate chemistry of water, leading to lower [CO₃^2-] (carbonate ion concentration) for shellfish to use to build their CaCO₃ shells. Shellfish in the earliest larval stages are particularly sensitive to low carbonate levels.

Monitoring water intake in shellfish hatcheries allows detection of low carbonate concentrations. The intake water can then either be buffered through addition of carbonate or shutdown until the conditions improve.