This U.S. Geological Survey (USGS) Data Release provides water-quality data collected from the Caloosahatchee River and 12 fiberglass tanks located within the Caloosahatchee River. The tanks were open to the atmosphere, and were closed to the river. Tanks were filled with native water within 1-2 hours prior to the first profile collected on May 6, July 8, and September 16. Nutrients were added at approximately 12:00 p.m. on May 6, 11:45 a.m. on July 8, and 11:00 a.m. on September 16. Sodium nitrate was added for the nitrate treatments, sodium phosphate was added for the phosphate treatments, and ammonium hydroxide was added for the ammonium treatments. Nutrient samples were collected and processed by Nova Southeastern University. Water-quality measurements were made at 3 depths within each fiberglass tank, near the surface (approximately 1 foot deep), near the middle of the water column, (approximately 2 feet deep) and near the bottom (approximately 3 feet deep), and at approximately 1, 2, and 3 feet deep within the river itself. Each depth location value represents an approximate 30 second average. Water-quality characteristics measured and recorded include water temperature, specific conductance, dissolved oxygen, pH, turbidity, chlorophyll fluorescence, phycocyanin fluorescence, and fluorescence of dissolved organic matter.