Actinic: A term used by many in our hobby to represent a blue fluorescent bulb. Originally blue bulbs called Actinic .03 bulbs were marketed by Philips. The blue bulbs appear to enhance the iridescent appearance of some corals. Currently, the term Actinic is used by many manufactures to represent their blue bulbs and I believe that rumors of special phosphors in the bulb are the urban legend. In actually, Actinic 03 as we know it was just a trade name and the actual definition of Actinic or Actinism is the "intrinsic property of radiation that produces photochemical activity."

Aragonite: The mineral form of crystalline calcium carbonate. In other words, sand or gravel made from calcium.

Ballast: An electrical device which provides power and load to a fluorescent or MH bulb.

Calcium Reactor: A device used to add calcium into the reef tank. A device which causes a calcium based material to dissolve faster than normal through the use of CO2, adding the calcium rich effluent into the tank.

Color Temperature: The temperature in degrees Kelvin that a bulb burns at. There is a relationship to the visible color of light the bulb produces and the temperature, but it is neither exact nor consistent. Typically, we want bulbs with color temps of greater than 5500k for our reef tanks. 6500k is usually considered yellowish-white, 7100k blue, 10000k white-blue and 12000k is blue-purple, but these colors can vary greatly between bulb manufactures, types, and wattages.

Cycle: The first few days to weeks of a new marine tank. In this time the nitrogen cycle is created. Food is usually introduced into the tank which when it breaks down results in ammonia. The ammonia spawns the growth in ammonia eating bacteria, which in turn produces nitrites, which is then converted into nitrates, which are finally consumed by your live rock and DSB. Warning, a cycle can occur even to a mature tank if a large fish dies, of if uncured live rock is added. Anything which causes an ammonia spike causes a cycle to ensue even if it's only for a day.

Detritus: Waste that collects on the sand and rocks.

Detrivore Kit: A collection of critters which are used to seed a sand bed with detritus eating creatures. Kits usually contain, but are not limited to, mysis shrimp, spaghetti worms, mini brittle stars, bristle worms, cepopods, and amphipods.

Diatom: single-celled, microscopic plant that secretes and is enclosed by an often intricate, round-to-elongated silica shell. (see rust on sand below)

DOC: Dissolved Organic Carbon (or Compounds). Organic matter in the water column. The organic matter which is removed by a protein skimmer.

Dosing Pump: A pump, usually of perastaltic or diaphragm design, which are used to administer medications, trace elements, or top off water to the tank.

Dry Foam: Common term referring to the consistency of the foam produced by a skimmer (foam fractionator). This foam is similar to the foam you create while washing dishes or taking a bubble bath, which you can scoop up with your hand, and it does not drip any water, it is dry.

Deep Sand Bed (DSB): Usually 4 to 6 or more inches deep. This deep sand provides an environment for aerobic and anaerobic nitrifying bacteria. A DSB will remove nitrate from your marine environment.

Hard Coral: An LPS or SPS coral. A coral with a hard skeleton and polyps which have 6 tenticles.

Kalkwasser: Powdered lime used to create a limewater solution for the purpose of adding calcium to the water. The limewater is then slowly dripped into the tank. Saturated, fresh limewater has a pH of 12.5.

LFS: Local Fish Store

Live Rock: Natural Reef, Aquacultured, or home made rock which has been in a marine environment long enough to be colonized by nitrifying bacteria.

Live Sand: Sand which has been in a marine environment long enough to be colonized by nitrifying bacteria. Good live sand will also contain sand dwelling creatures such as worms, microcrustations, snails, etc.

LPS: Large Polyp Stony (Scleractinia) coral. A hard coral. (ex. open brain)

Marine Snow: Refers to the particulate matter which is present in the water around a reef or in out tanks. Most filter feeders capture this marine snow for food. It is also the name of a product that is supposed to simulate the condition.

MH: Metal Halide bulb. A very intense gas filled bulb. Other types which fall into this class are mercury vapor and HQI.

MO: Mail Order

NO: Normal Output fluorescent bulb. These are the type used in most home applications. A typical 4ft bulb is 40 watts.

Oolitic Sand: Small, round grained calcareous sugar-size sand. This sand is excellent for use in a Deep Sand Bed (DSB)

PAR: Photosynthetic Available Radiation. Considered by experts to be the best method of ascertaining the benefit of a lamp on photosynthetic animals and plants. It utilizes quantum units to determine the amount and quality of light available for photosynthesis. Use this measurement when designing a lighting system for your reef.

PC or CF: Power Compact or Compact Fluorescent bulb. Each bulb actually has at least 2 tubes allowing for a 3 ft bulb to produce 96 watts.

Photoadaptation: The ability of a photosynthetic organism to adjust its structure to compensate for various lighting environments.

Photosynthesis: The process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source.

Phytoplankton: Minute, free floating aquatic plants. This algae is at the bottom of the food chain and used for food by everything from tiny filter feeders to clams and corals. Phytoplankton is available in live cultures from DT's, cryopreserved by Brine Shrimp Direct, and dried by Kent.

Power Head: Small, submersible pump usually placed in aquariums to provide water circulation.

Protein Skimmer: A foam fractionator. A device which causes the water to foam (much like blowing into a straw in your ice cream soda). The organic compounds in the water cling to the tiny bubbles eventually making it out of the skimmer into a collection cup. The resultant, stinky waste is affectionately referred to as skimmate.

RO, RO/DI, DI: Methods of removing all the impurities from your water. You should use only this purified water for your tank. Britta water filters wont cut it, store bought distilled water could have copper from the distilling process and is not recommended either.

Refugium: An area in a display tank, sump, or separate tank which provides an environment for creatures to grow without fear of predation.

Rust on sand and rocks: The rust colored dust on rocks, sand, and glass is really diatoms. It is a normal occurrence in a new tank. Diatoms feed on silicate, a normal source of which is the tap water you used to rinse out your sand or gravel. This too shall pass as long as your are using RO or DI water. (see diatom above)

Soft Coral: A coral which does not have a hard skeleton (there are a few exceptions). Example, finger leather, toadstool, xenia.

SPS: Small Polyp Stony (Scleractinia) coral. A hard coral. (ex. acropora).

Sump: A container which is plumbed into the water system of a display tank. The sump can be a plastic tub, small aquarium, or a tank specially designed for the purpose. A sump has many uses:

• To provide additional water volume.
  
• To provide a place to put pumps, skimmers, heaters.
  
• To provide a refugia
  
• To provide a place for additional Live Rock, sand, macro algae.
  

VHO: Very High Output fluorescent bulb. A typical 4 ft bulb is 110 watts.

Watts/gal: Is commonly used to size a lighting system for a reef but is now considered to be largely useless. The old rule of thumb for light hungry corals was about 8 watts/gal.

WaveMaker: A switching device used to turn on and off pumps to create an artificial surf or current in our reef tanks.

Zooxanthellae: The symbiotic algae that live in the cells of photosynthetic corals and converts light to carbohydrates.