Fluval Sea Alkalinity is a concentrated, alkalinity-boosting compound that provides an important energy source for supporting strong coral growth and plays a key role in maintaining optimal pH levels. Fluval Sea Alkalinity contains USP (Pharmaceutical) Grade sodium carbonate, sodium bicarbonate and sodium borate, which ensure that you're getting a high quality and ultra pure product that's free of unwanted contaminates. It does not contain gluconates, nitrates, phosphates. Fluval Sea Alkalinity is strongly recommended to offset constant depletion of alkalinity by coral, buffering, coralline algae and natural ongoing biological processes.