Total Suspended Solids (TSS)

Total Suspended Solids is the gravimetric measurement of all particulate matter suspended in a water sample — uneaten feed, feces, algae, bacteria flocs, and mineral silt — determined by filtering a known volume through a standardized filter and drying the captured residue at 103–105°C, reported in mg/L. Interpretation is context-dependent but experience gives anchors: under about 10 mg/L water is visibly clear; 15–40 mg/L is typical of a healthy productive pond with an algal bloom; above roughly 80–100 mg/L, and especially when solids are organic, gill irritation, light suppression, and oxygen demand become management concerns. Physically, elevated TSS damages gill epithelium through abrasion and clogging, raising susceptibility to gill disease; optically, it attenuates light and suppresses the photosynthesis that many ponds depend on; and chemically, the organic fraction is a standing oxygen debt — decomposing suspended solids consume dissolved oxygen around the clock and can drive dawn crashes, linking TSS directly to aeration requirements. As a system indicator, TSS trends in tanks and RAS reveal feeding accuracy, filter performance, and biofloc density cheaply, and it is also a regulated effluent parameter in most jurisdictions, since discharged solids smother benthic habitat and cloud receiving waters independent of their nutrient content; effluent limits typically sit in the tens of mg/L, pushing farms toward settlement, filtration, or reuse before discharge.