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Reefkeeping Acronyms

Here's a guide to help you figure out just what marine and other aquarists are talking about!

shortcut: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Ampere Measure of the amount of electric charge passing a point per unit time. Around 6.241 ? 1018 electrons passing a given point each second constitutes one ampere.[
AA Amino Acid Building block units of proteins
AC Activated Carbon Adsorbent filtration media used to remove trace organic compounds from water
AC Alternating Current An electric current that reverses direction in a circuit at regular intervals.
AC II AquaController II A all in one monitor and controller to control and monitor pH, ORP,

and temperature
Acan(s) Acanthastrea A fairly large genus in the family Mussidae, consisting of twelve species
Acan Lord Acanthastrea species Acanthastrea lordhowensis
Acro Acropora A genus of scleractinian coral in the Phylum Cnidaria, common names include table coral, elkhorn coral, or staghorn coral
AEFW Acropora Eating Flat Worms A parasite of some species of Acropora corals
AFI Aquarium Fish International Magazine
AFM Aquarium Fish Monthly Magazine
AGA All Glass Aquarium Type of aquarium or manufacturer
AGE Acrylic and Glass Exhibits Reference to types of materials used in construction aquaria tanks

and exhibits
ALK, Alk Alkalinity Is the sum of titratable carbonate and noncarbonate chemical species in a filtered water sample
AM3K Ampmaster 3000 Water pump model made by Dolphin Aquarium & Pet Products, Inc.
ARS Aquatic Reef Systems RO/DI manufacturer,
ASW Artificial Sea Water Salt water mixed from components
ATC Automatic Temperature Control Device that allows you to choose selectable heating and cooling

ATO Automatic Top Off System to automatically replace water in your aquarium lost to

ATS Automatic Turf Scrubber Method of filtration
ATZ  Association of Zoos & Aquariums Nonprofit organization that accredits zoos and aquariums
BB Bare Bottom Aquarium set up without sand
Blasto Blastomussa Genus of coral, members are wellsi and merleti
BLH Blue Leg Hermit Crab Cibanarius sp., used for scavenging habits
BOD Biological Oxygen Demand The amount of oxygen that would be consumed if all the organics in one liter of water were oxidized by bacteria and protozoa.
BR Base Rock Generic term for aragonite rocks which have no bacterial organisms

or coralline algae growing in or on the rock
BS Brittle Starfish Class Ophiuroidea, related to starfish but have long, flexible arms.
BTA Bubble Tipped Anemone Entacmaea quadricolor, a species of of sea anemone of Indo-Pacific origin
BTU British Thermal Unit Unit of energy equal to about 1 055.05585 joules. It is approximately the amount of energy needed to heat 1 pound (0.454 kg) of water 1 ?F (0.556 ?C)
BYA Bubble Tip Anemone Type of anemone; signature of being the bulb tips that form towards the ends of the anemone?s tentacles.
BZA  Blue Zoo Aquatics Vendor of aquariums, supplies, and stock
Ca Calcium Chemical symbol for the element Calcium
CA Custom Aquatic Supplier of fresh and marine aquarium supplies and stock
CaCl2, CACL2 Calcium Chloride Chemical formula for salt
CaCO3, CACO3 Calcium Carbonate Main component of corals, shells of marine organisms, snails
Ca(OH)2 CAOH2 Calcium Hydroxide Calcium based powder use to make Kalkwasser
CB Coral Beauty Angelfish Centropyge bispinosus, commonly available marine angelfish
CBB Copper Band Butterfly Chelmon rostratus, also know as Beaked Coral Fish, Beaked Butterfly Fish
CBS Coral Banded Shrimp Stenopus hispidus, popular in reef and marine aquariums
CC Counter Current Typically refers to a type of skimmer
CC Crushed Coral Type of substrate used, generally 1/8" ? 3/16" size pieces
CL Closed Loop A reef tank system set up that  work by taking water out and sending it back in through various mechanical means to make flow in a tank.
CO2, CO2 Carbon Dioxide Colorless gas
CO3, CO3 Carbonate A salt of carbonic acid, combines with other elements to form

carbonates like CaCO3
CPR Creative Plastics Research Manufacturer of fresh and saltwater products
CSL Custom Sea Life Aquarium lighting manufacturer
CTA Cellulose Ariacetate Can be used as a semi-permeable membrane in reverse osmosis systems
Cu Copper Chemical symbol for the metallic element Copper
CUC Clean Up Crew Group of invertebrates like snails, micro-crabs, cucumbers, and

such, that that eat / remove algae and detritus.
CVR Central Valley Reefers Local Marine Club located in Central Valley, California
CWCS Continuous Water Change System A set-up used to achieve the results of weekly water changes
Cyano Cyanobacteria Bacteria species often referred to as slime algae
C2C  Coast to Coast Refers to distance spanning USA
DC Direct Curent The unidirectional flow of electric charge produced by sources like batteries, thermocouples, solar cells, etc.
DD Down Draft Type of protein skimmer
DE Double Ended Generally referring to types of bulbs used in aquarium lighting fixtures
DFS Doctors Foster & Smith Online pet supply store
DI Deionization Type of water purification that removes charged ion species
DIY Do It Yourself Implies project or process can by done by the average person
dKH Degrees of Calcium Hardness A way to measure alkalinity
DO Dissolved Oxygen The amount of dissolved oxygen gas, 02, dissolved in water
DOC Dissolved Organic Carbon Describes all the dissolved compounds found in water that derive from organic materials
DSB Deep Sand Bed Bed of sand in an aquarium generally 3"-4" or more deep
DT Display Tank Any aquarium tank keeping fish or other aquatic life
DT?s  ?? Brand of phytoplankton
EB Electronic Ballast Type of ballasts used in aquarium light fixtures. Ballasts stabilize the current of gas-conducted fluorescent lights, compact fluorescents and halides
EC Emerald Crab Mithrax sculptus, kept for scavenging habits.
EC End Cap End fitting on T5 bulbs.
ETA Estimated Time of Arrival General use acronym
ER  Euro-Reef Skimmer manufacturer
FAMA Fresh and Marine Aquaria A stand alone magazine at one time, now part of Aquarium Fish International
FAQ Frequently Asked Questions Common speech and text acronym
Fe, FE Iron Symbol for elemental iron
FFE Flying Fish Express Online livestock dealer now owned by pet dealer Drs. Foster and Smith
FO Fish Only Reef aquarium with no corals or live rock
FOWLR Fish Only with Live Rock Reef aquarium with live rock, no corals
FTS Full Tank Shot A photograph showing the entire aquarium tank
Fuge Short for Refugium A tank isolated, but connected to the main display tank that allows for common water filtration while at the same time keeping more aggressive fish from impacting its inhabitants.
FW Fresh Water Refers to aquariums that are non-saltwater
FW Flat Worms Platyhelminths common in tanks, most are harmless or even potentially beneficial to a reef tank. Can commonly reference reef tank pest Red Planaria
FWE Flat Worm Exit Product used to kill flatworm (Red Planaria) in reef and

marine tanks
FYI For Your Information General speech acronym
FYM  For Your Mis-information General speech acronym
GAC Granular Activated Carbon Adsorbent filtration media that has been crushed into granules; used to remove trace organic compounds from water
GAL Gallon Measure of volume approximately equal to 3.79 liters
GBP Green Button Polyps Colonies of small anemone looking polyps similar to Zoanthids in a wide range of colors including green
GBR Great Barrier Reef World?s largest reef system in the Coral Sea off NE coast of Australia
GBTA Green Bubble Tip Anemone Standard color morphs of Entacmaea quadricolor (others are rose, orange, and red)
GFO Granular Ferric Oxide Ferric Iron (Fe+++) based phosphate binding material used in filtration
GFCI Ground Fault Circuit Interrupter Type of AC plug with a fast-acting circuit breaker that senses small imbalances in an electrical circuit caused by the electrical current leaking to ground. If this imbalance occurs, the GFCI shuts off the electricity within a fraction of a second.
GFI Ground Fault Interrupter Another name for GFCI; see above
GFO Granular Ferric Oxide Used to bind, remove, and control levels of phosphate in reef aquariums
GHA Green Hair Algae A form of algae (Derbesia) that looks like hair, can grow rapidly out of control.
GOB Green Open Brain Trachyphyllia geoffroyi, type of coral in the wild found in the sand.
GPD Gallons Per Day Flow rate measurement
GPH Gallons Per Hour Flow rate measurement
GPM Gallons Per Minute Flow rate measurement
GSM Gold Striped Maroon Species of clown fish (Premnas biaculeatus)
GSP  Green Star Polyps Small bright green polyps connected together by a rubbery purple colored mat. Open during the day, retracted at night or when disturbed.
H Hydrogen Chemical symbol for the element Hydrogen
HA Hair Algae Light green or green-gray type of algae that can become a nuisance in the aquarium
HCO3, HCO3 Hydrogen Carbonate Another name for bicarbonate
HID High Intensity Discharge Type of lighting
HITH Hole in the Head Disease of tropical fish
HLLE Head and Lateral Line Erosion Fish disease that affects both freshwater and marine fish. Also known as hole-in-head disease.
HO High Output Type of fluorescent lighting used in marine aquaria tanks
HOB Hang on Back Term generally used to describe a type of skimmer that hangs on the back of an aquarium tank
HOT Hang on Tank Describes how and item affixes to an aquarium tank
HPS High Pressure Sodium Type of lighting primarily used for outdoor security lighting and indoor gardening.
HSA High Speed Aeration Type of protein skimmer
HQI  Mercury Quartz Iodide Type of metal halide lamp. The H referrers to Mercury by its chemical symbol, Hg
I- Iodide One of the largest (monoatomic) anions
I Iodine Chemical symbol for element; occurs in slightly greater concentrations in seawater than in rocks. It normally exists as a diatomic molecule I2
I2 Iodine Naturally occurring form of element Iodine (I)
IA Inland Aquatics Store selling captive reared and tank raised corals, fishes, and marine invertebrates
Ich, Ick Ichthyophthirius multifilis Common fish disease easily recognizable by its white cottony spots or strings.
IO Instant Ocean Brand of aquarium salt
IO3, IO3 Iodate A salt containing 1 Iodine bonded to three oxygen atoms and found in seawater
IPSF Indo-Pacific Sea Farms Online retailer of captive bred marine life.
IR Infrared The band of the light spectrum that lies between the visible and microwave portions of the electromagnetic spectrum
IW   In Wall A tank mounted in a wall, typically with only one viewable side
K Kelvin Refers to either a unit of measure of temperature on the thermodynamic (absolute) temperature scale or to a lighting rating where color temperature is a measurement in degrees Kelvin that indicates the hue of a specific type of light source.
Kalk, KW Kalk?v?asser German term for calcium hydroxide solution or lime water
KI Potassium Iodide Chemical symbol for the compound Potassium (K) Iodide (I) used to replenish Iodine in reef tanks.
kWh   Kilowatt Hour Unit of energy equal to 1000 watt hours where watt hours is the multiplication of power in watts and time in hours. It is the billing unit of energy delivered to consumers by electric utilities.
L or l Liter, Litre Metric unit of volume ? 0.264 gallons US
LA Live Aquaria Online dealer of fresh and marine plants and animals
LA3 or L3 LumenArc 3 Type of aquarium lighting reflector
Lb. or Lbs Pounds Unit of mass
LED Light Emitting Diode A semiconductor light source used as indicator lamps in many devices, and increasingly used for lighting.
LFS Local Fish Store Refers to any local brick and mortar store selling aqua related items
LHS Local Hardware Store Refers to any local brick and mortar store selling hardware and related items
LMB Lawn Mower Blenny Salarias fasciatus; noted for its ability to keep algae growth, especially hair algae, in the check in marine aquariums.
Lobo Lobophyllia Brain coral species that is a large polyp stony coral noted for its varied colors, shapes, and patterns.
Lord Lordhowensis Also, "The Lord," a common species of Acanthastrea.
LPH Liters Per Hour Flow rate measurement
LPS Large Polyp Scleractinian Type of coral defined by polyp size (~ 1cm and up) and belonging to the order of stony corals, Scleractinian, which build calcium carbonate skeletons as they grow.
LR Live Rock Rock containing Coralline algae and inhabited by a multitude of marine organisms used in marine aquariums because of benefits it provides to these closed systems.
LS Live Sand Coral sand that has the microscopic biological bacteria that grows on it, and the many tiny crustaceans and other micro and macro-organisms that reside in it. used in marine aquariums because of benefits it provides to these closed systems.
LSB Live Sand Bed Sand bed with living organisms residing in it
LRB Little Red Bugs Common parasitic crustacean that infects only Acropora species of SPS corals
LTA  Long Tentacle Anemone Macrodactyla doreensis, also referred to as the Corkscrew Anemone
MACNA Marine Aquaria Conference of North America Conference held annually and hosted in different locations each year
MASNA Marine Aquarium Societies of North America A non-profit organization composed of marine aquarium clubs and individual hobbyists from North America and abroad
MB Magnetic Ballast A type of ballast that uses a magnetic core to regulate the voltage of a fluorescent light
MD Marine Depot Online source for aquarium pet fish supplies, fish tank accessories, products and equipment
meq/L or MEQ/L Millieqivalents Per Liter Measurement of alkalinity
MARS Marine Aquarist Round Table of Sacramento Local marine club located in Sacramento, California
Mg or Mag Magnesium Chemical symbol for the element Magnesium
MG/L Milligrams Per Liter Metric measurement of concentration
MH Metal Halide Type of lamp used in aquarium lighting
Micro Micromussa Coral species characterized by 5-6 millimeter corallites that are cerioid (shares the same wall with each other)
Milli Acropora Millepora A SPS coral that grows mostly vertically, which leads to a bushy morphology that is semi-erect. Polyps extend from vertical branch tips.
MJ Maxi Jet Brand of pumps used in fresh and marine systems
MM Miracle Mud A brand of refugium mud substrate
MN Montipora Nudibranch Nudibranch pest that affects SPS corals
MO Mail Order Referring to items purchased by mail
MV  Mercury Vapor Type of lighting.
N Nitrogen Symbol for the chemical element Nitrogen, composes

78.08% by volume of earths air.
Na Sodium Symbol for the chemical element sodium
NaCO3, NaCO3 Sodium Carbonate Incorrect formula used to designate carbonate ion form NaHCO3 a buffering agent.
NaOH Sodium Hydroxide Chemical commonly used to adjust pH and alkalinity in aquaria
NH3, NH3 Ammonia Compound composed of Nitrogen (N) and 3 Hydrogen (H) atoms. In aquariums produced by the decomposition of organics. Very toxic to fish
NNR Natural Nitrate Reduction Method of aquarium filtration developed by Dr. Jaubert; consists of a Deep Sand Bed (DSB), a plenum and a protein skimmer.
NO Normal Output Type of fluorescent light
NO2, NO2 Nitrite Compound composed of Nitrogen (N) and 2 Hydrogen (H) atoms. What Ammonia is converted to by nitrogen-fixing bacteria in fresh and marine aquariums. Toxic to fish
NO3, NO3 Nitrate Compound composed of Nitrogen (N) and 1 Hydrogen (H) atom. The product from Nitrobacter bacteria converting Nitrite in fresh and marine aquariums.
NPS Non Photosynthetic Corals that do not contain photosynthetic algae and strictly filter feed. Common genus include  Tubastrea ("Sun Coral"), Dendrophyllia ("Dendros") and Balanophyllia ("Balanos")
NSW Natural Sea Water Sea or ocean water
NTS New Tank Syndrome The period in which ammonia and then nitrite levels rise to dangerous quantities before being converted into relatively harmless nitrate in a newly setup tank.
NTTH New to the hobby common acronym used in forums
NVR  Northern Valley Reefers Local reefkeeping club in Central Valley, CA
O Oxygen Chemical symbol for the element oxygen; a colorless and odorless gas
O2, O2 Oxygen How oxygen occurs naturally in the air; as a pair of oxygen atoms
OM Ocean Motions Four way pump.
OP Original Poster Person who initially started a thread on a message board or forum.
ORP Oxidation Reduction Potential Measure of a systems ability to oxidize material. In general, oxidation occurs if the oxygen content of a covalently bonded molecule increases or if the hydrogen content decreases.
OTS  Old Tank Syndrome Generally the result of gradual changes occurring in the water over a long period of time (many weeks to many months or even years ). Often recognized when old fish remain fine, but new fish die.
PA Premium Aquatics Retailer of livestock and marine aquarium supplies
PAR Photosynthetic Active Radiation Measure of irradiance, the amount of sunlight or ambient light that diffuses through water compared to surface light. Focuses on the dynamics of the photic zone, ~1-5 meters below the surface
PB Pulse Ballast Type of light ballast using a high-voltage igniter that works with the ballast to start the lamp using a series of high-voltage pulses.
PBITAWA Pour Bleach In Tank And Walk Away Acronym used to insult or joke with a user on a reef-related forum referring implying that the situation is hopeless or will require a lot of work to correct.
PBT Powder Blue Tank Acanthurus leucosternon. Marine tank fish prized for its vivid colors and bold markings.
PC Power Compact Type of fluorescent light
PE Polyp Extension When corals extend their polyps out from their stony housings
PFO ?? Lighting manufacturer
PH Power Head Type of internal water pump
pH Potential Hydrogen Or Potenz (power) Hydrogen; measure of acidity or alkalinity.
PM Precision Marine Marine filtration component manufacturer
PO4, PO4 Phosphate Compound composed of Phosphate (P) and 4 Oxygen (O). Used as food by aquarium algae.
Pods Copepods A very diverse group of crustaceans found in marine and freshwater environments.
PPB Parts Per Billion Measurement of concentration
PPM Parts Per Million Measurement of concentration
PPT Parts Per Thousand Measurement of concentration
PS Protein Skimmer Device used in marine aquariums to remove proteins
PUR  Photosynthetically Usable Radiation The usable portion of PAR, and different photosynthetic species will have a different PUR range to which they respond.
PVC Poly Vinyl Chloride Type of plastics commonly used in plumbing
QT Quarantine Tank Tank used to sequester and protect an exiting tank by allowing new fish to regain optimum health before their introduction into the main tank.
RBTA Rose Bubble Tipped Anemone A less common form of the Bubble Tip Anemone
RC Reef Central Online aquaria bulletin board community
RC Reef Crystals Brand of marine aquarium salt
RDO Reefs.org Aquarium bulletin board
RDSD Remote Deep Sand Bed Option used to filter nitrates from a reef system
Rics Ricordea Genus of  of mushroom coral of moderate size. It can be identified by the fact that it has contrasting raised dots across its surface
RK Reef Keeping Online aquarium magazine
RLH Red Leg Hermit Crab Paguristes cadenati, used as algae eater and scavenger
RO Reverse Osmosis Type of water purification
RO/DI Reverse Osmosis /Deionization Combination of water purification processes commonly found in systems used by aquarists to create purified water.
ROB Red Open Brain Trachyphyllia geoffroyi, seen in different red variatoins as well as green. Also know as Folded Brain Coral, Crater

Coral, Round Brain Coral
RR Reef Ready Aquarium that has pre-drilled holes and overflows
RS, RSS Red Sea, Red Sea Salt Brand name
RSM Red Slime Remover Commercial product for removing red slime algae (cyanobacteria)

from tanks
RTN Rapid Tissue Necrosis A type protozoa infection of corals
RUGF  Reverse Under Gravel Filter Filter system where ater is pumped down through the "uplift" tubes and then rises up through the gravel. The water is mechanically pre-filtered before it is pumped.
SAL Salinity Measure of the dissolved salt content of a body of water, expressed by the amount of salt found in 1000 grams of water or ppt
Saki Iwasaki Lighting manufacturer
SEAbay Saltwater Enthusiast Association of the Bay Area Reef Club located in northern California
SB Sandbed Layer of sand on aquarium bottom
SCWD Switching Current Water Director 3iQ Ventures wave making product for aquariums, pronounced "squid"
SD Southdown Type of sand
SE Single Ended Type of lamp used in aquarium lighting
SG Specific Gravity Physical property used to measure saltwater density
SHO Super High Output Fluorescent light, equivalent to power compact

Shrooms Mushrooms Belong to the order corallimorpharia, look like both anemones and true corals but are neither.
Si Silicon A chemical element and found in sands, dusts, and rock primarily as silicon dioxide or silicates
SiO2, SiO2 Silicon Dioxide Commonly found form of silicon
SPS Small Polyp Scleractinian Type of coral defined by polyp size (~ under 1cm) and belonging to the order of stony corals, Scleractinian, which build calcium carbonate skeletons as they grow.
Sr Strontium Chemical element, can be combined place of calcium in deposited calcium carbonate.
SSB Shallow Sand Bed Sand bed generally less than 3" deep
Sticky ?? Refers to postings in forum threads that always stay at top, regardless of original date of post
STN Slow Tissue Necrosis Type of protozoa infection of corals
SW  Salt Water / Sea Water Ocean, sea or water created to simulate these
T# ?- Measurement of fluorescent bulb diameter in 1/8" increments. i.e. a T5 is 5/8", a T12 is 1.5"
TAR ? Type of magnetic ballast
TBS Tampa Bay Saltwater Producer of live rock
TDS Total Dissolved Solids Portion of solids in water that can pass through a 2 micron filter
TFC Thin Film Composite Type of reverse osmosis membrane
TIC Total Inorganic Carbon The sum of inorganic carbon species in a solution
TM Tropic Marin Brand of sea salt and aquarium supplies
TOC Total Organic Carbon The amount of carbon bound in an organic compounds
TOTM Tank of the Month Featured tank on a forum or website
Trachy Trachyphyllia Brain coral
TRT The Reef Tank Online forum
TWP  Tap Water Purifier Device used to filter tap water; product for filtering tap water from Aquatic Pharmaceuticals
UGF Under Gravel Filter Aquarium filtration system installed under the substrate covering the tank bottom.
ULNS Ultra Low Nutrient System Refers to ideal aquarium set up where water quality that

is as good as nature; stable without parameter swings.
UV  Ultra Violet Portion of light spectrum with a wavelength shorter than that of visible light, but longer than X-rays.
V Volt SI derived unit of electromotive force, commonly called

VHO Very High Output Type of fluorescent lighting
VSV  Vodka ,Sugar or Vinegar Mix used for carbon dosing reef aquariums
W Watts Unit of power that measures the rate of energy conversion. It is defined as one joule per second.
WC Water Change Refers to removing and replacing a quantity of water in a tank.
WD Wet Dry Method of aquarium filtration
Wellso Wellsophyllia Dated term for brain coral now referred to as Trachyphylliidae radiata coral
WH Wiring Harness Part used in aquarium lighting setups
WNL Within Normal Limits Reference to test results that fall within established

WPG Watts Per Gallon Method of measuring light requirements
WPS White Star Polyps Pachyclavularia species, also occur in brown and green
WSM White Stripe Maroon Premnas biaculeatus, variety of Clownfish
WTB Want to Buy Common acronym used on forums
WTS Want to Sell Common acronym used on forums
WTT Want to Trade Common acronym used on forums
WQ Water Quality Measure of the degree of water purity
WYSIWYG What You See Is What You Get Common acronym used on forums
X10 ?? Company that makes automation and control products
YWG Yellow Watchman Goby Cyrptocentrus cinctus; also know as Yellow Watchman Prawn, or Yellow Shrimp Goby
Zoas, Zoos Zooanthids Soft corals of genus Zoanthus, commonly referred to Button Polyps, Colonial Anemones, or Sea Mats. They resemble clusters of miniature sea anemones.

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