Sulfur is an element present in seawater and reef tank organic matter, involved in various biological processes and certain bacterial denitrification methods. It’s rarely tested directly but plays a background role in several reef keeping practices.

Chelation is a chemical process in which an organic molecule binds tightly to a metal ion, keeping it dissolved and bioavailable rather than allowing it to precipitate out of the water. It’s commonly used in trace element supplements to improve stability and uptake.

Nutrient uptake refers to the process by which corals, algae, and bacteria absorb dissolved nutrients like nitrate and phosphate from aquarium water. It’s a key natural mechanism working alongside active nutrient export methods.

A reef aquarium is a marine tank specifically designed to house and support live coral alongside fish and other invertebrates. It requires more specialized equipment and closer attention to water chemistry than a standard fish-only tank.

Iron is a trace element that supports certain algae and coral pigmentation processes, though it’s more commonly discussed in reef keeping for its role in GFO media. Supplementation is generally approached conservatively and based on testing.

A dosing pump is a piece of equipment that automatically delivers precise, scheduled amounts of liquid supplements like calcium and alkalinity into a reef tank. It removes the need for manual daily dosing, improving consistency and convenience.

Base rock is the dry, structural rock used to build the physical foundation of a reef aquascape. Typically made from calcium carbonate material, it starts out biologically inert but gradually becomes colonized by beneficial bacteria and coralline algae as the tank matures.

TDS, or total dissolved solids, measures the combined concentration of all dissolved minerals and impurities in water. Reef keepers use TDS readings primarily to verify that RODI purification equipment is performing effectively before use.

A chiller is a piece of equipment that actively cools aquarium water to maintain a stable, appropriate temperature. It’s especially important in warm climates or systems with significant heat output from lighting and pumps, where water can otherwise run too warm.

Ionic balance refers to the proper ratio of major ions in reef tank water, closely mirroring natural seawater’s composition. Maintaining this balance supports stable water chemistry and healthy biological processes throughout the tank.

Nutrient limitation occurs when available nutrients like nitrate or phosphate become too scarce to support healthy coral growth and function. It’s the opposite extreme of nutrient excess, and can be just as harmful to reef tank health.

Reduction is a chemical reaction in which a substance gains electrons, the paired counterpart to oxidation. Together these two processes underlie ORP measurements and various natural water quality dynamics within a reef tank.

Lithium is a trace element present in natural seawater in very small amounts, with a still poorly understood role in reef tank biology. It’s rarely tested or dosed directly, typically appearing only as one line item on a comprehensive ICP report.

Element accumulation refers to the gradual buildup of a trace or major element in aquarium water beyond its natural or intended range, often from over-dosing or an imbalanced salt mix. Left unchecked, it can become harmful to sensitive corals and invertebrates.

Temperature is a fundamental water parameter affecting metabolic rate, oxygen solubility, and overall livestock health in a reef tank. Most reef tanks target a stable range closely mirroring natural tropical reef conditions year-round.

Chlorine is a chemical disinfectant commonly added to municipal tap water to control bacteria and pathogens. While effective for drinking water safety, it’s toxic to fish, invertebrates, and beneficial bacteria, so it must be fully removed before that water is used in a reef tank.

Kalkwasser, German for lime water, is a calcium hydroxide solution used to simultaneously raise calcium and alkalinity while buffering pH. It’s a traditional, cost-effective supplementation method still popular in the reef keeping hobby.

Reef chemistry refers to the broad study and management of water parameters that support coral health, from major elements like calcium to trace elements and nutrients. It’s the foundational knowledge base behind successful reef keeping.

Organic carbon refers to carbon-containing compounds from living or once-living sources, present in aquarium water as dissolved waste and decaying matter. It’s central to both natural bacterial processes and deliberate carbon dosing for nutrient export.

A TDS meter is a handheld device that measures total dissolved solids in water by reading its electrical conductivity. Reef keepers use it primarily to verify RODI purification equipment is producing adequately pure water.