AB
Aqualine Buschke, lighting manufacturer
AC
Activated carbon, chemical filtration media / alternating current
AC II
AquaController II, all-in-one monitor & controller
acro
Acropora, a type of SPS coral
AFAIK
As far as I know
AFM
Aquarium Fish Monthly, magazine
AGA
All-Glass Aquarium, aquarium manufacturer
AL
Aqualink, aquarium bulletin board
ALK
Alkalinity, measure of buffering capacity of water
AM3K
Ampmaster 3000, a model of water pump made by Dolphin Aquarium & Pet Products, Inc.
ARS
Aquatic Reef Systems, RO/DI mail order place
ASAP
As soon as possible
ATC
Automatic temperature compensating, a feature on some refractometers
ATM
At the moment
ATS
Algae turf scrubber, reef setup technique
Bfly
Butterflyfish
BOD
Biological oxygen demand
BTA
Type of anemone (Entacmaea quadricolor) / bubble-tipped, bulb tentacle, bulb tip
BTW
By the way
Ca
Calcium
CA
Custom Aquatic, mail order place
CaCl2
Calcium chloride
CaCO3
Calcium carbonate
Ca(OH)2
Calcium hydroxide
CC
Crushed coral / Counter current, type of protein skimmer
Cl
Chlorine
CO2
Carbon dioxide
CO3
Carbonate
CPR
Creative Plastics Research, manufacturer of fresh and saltwater products
CSL
Custom Sea Life, lighting manufacturer
CTA
Cellulose triacetate, type of RO membrane
Cu
Copper
CYANO
Cyanobacteria
DD
Downdraft, type of protein skimmer
DE
Double ended metal halide metal bulb
DFS
Drs. Foster & Smith, Inc., mail order place
DI
Deionization, type of water purification
DIY
Do it yourself
dKH
Degrees of carbonate hardness, measure of alkalinity
DO
Dissolve oxygen
DOC
Dissolved organic carbon
DSB
Deep sand bed
DT's
Brand of refrigerated living phytoplankton
ER
Euro-Reef, skimmer manufacturer
FAMA
Freshwater and Marine Aquarium magazine
FAQ
Frequently asked questions
Fe
Iron
FFE
Flying Fish Express, mail order place
FO
Fish only, type of marine aquarium
FOWLR
Fish Only with Live Rock
frag(s)
Broken or cut pieces of coral which will eventually grow into a new animal
"fuge"
Short for refugium
FW
Freshwater
FWIW
For what its worth
FYI
For your information
FYM
For your misinformation
GAC
Granular activated carbon, chemical filtration media
GAL
Gallon
GBR
Great Barrier Reef
GFCI/GFI
Ground fault circuit interrupter / Ground fault interrupter
GPH
Gallons per hour
GOB
Green open brain
GSP
Green star polyps
HCO3
Hydrogen carbonate
HD
Home Depot
HID
High intensity discharge, type of light
HO
High output fluorescent light
HOT
Hang on top, type of skimmer
HPS
High pressure sodium, type of light NOT for reefs but the ballasts concern them
HQI
High quartz iodide, type of light
HSA
High speed aeration, type of proteins skimmer
HTH
Hope this helps
I
Iodide
I2
Iodine
IA
Inland Aquatics, mail order company
ID
Identify/Identity
IIRC
If I recall correctly
IM
In my
IMCO
In my considered opinion
IME
In my experience
IMEO
In my expert opinion
IMHO
In my humble/honest opinion
IMNSHO
In my not so humble/honest opinion
IMO
In my opinion
IO
Instant Ocean, brand of synthetic salt mix
IO3
Iodate
IOW
In other words
IPSF
Indo-Pacific Sea Farms, mail order place
IR
Infrared, type of light of longer wavelength than visible light
IRC
Internet relay chat
ISP
Internet service provider
JME
Just my experience.
JMO
Just my opinion.
K
kelvin (mechanism for measuring spectrum of lighting, should be labeled degrees K) / Potassium
KALK
Kalkwasser, German for calcium hydroxide solution or limewater
KI
Potassium iodide
KISS
Keep it simple stupid
L
Liter
LED
Light emiting diode
LFS
Local fish store
LHS
Local hardware store
LMAO
Laughing my *** off
LOL
Laughing out loud
LPS
Large polyped Scleractinian (stoney) coral
LR
Live rock
LS
Live sand
LT
Litre
LTA
Type of anemone (Macrodactyla doreensis) / Long tentacle anemone
MACNA
Marine Aquaria Conference of North America, held annually
MD
Marine Depot, mail order place
MEQ/L
Milli-equivalents per litre, measure of alkalinity
Mg
Magnesium
Mg/L
Milligrams per litre
MH
Metal halide light
MJ
Maxijet, powerhead manufacturer
MM
Miracle Mud, method of aquarium filtration
MO
Mail order
MV
Mercury vapor, type of light
Na
Sodium
NaCO3
Sodium carbonate
NaOH
Sodium hydroxide
NFW
No way
NH3
Ammonia
NH4
Ammonium
NNR
Natural nitrate reduction, reef setup technique
NO
Normal output fluorescent light
NO2
Nitrite
NO3
Nitrate
NP
No problem
NRN
No reply necessary
NSW
Natural seawater
O2
Oxygen
OBTW
Oh by the way
ORP
Oxidation reduction potential, the ability to take or give electrons
OTOH
On the other hand
PA
Premium Aquatics, mail order place
PAR
Photosynthetically active radiation, lighting quantity
PC
Power compact fluorescent light
PFO
Lighting manufacturer
pH
Measure of the concentration of hydrogen ions, equal to -log[H+]
PH
Powerhead, water pump
PITA
Pain in the @ss
PLS
Please
PM
Precision Marine, marine filtration component manufacturer
PO4
Phosphate
"pods"
Non-specific types of copepods, amphipods and such
POS
Piece of doodoo
PPM
Parts per million, equivalent to mg/l (milligrams per litre)
PUR
Photosynthetically usuable radiation, lighting quantity
PVC
Poly vinyl chloride, used for piping / plumbing
RC
Reef Central, aquarium bulletin board supreme
RDO
Reefs.org ("reefs-dot-org"), aquarium bulletin board
RK
Reef Keeping, on-line aquarium magazine
RO
Reverse osmosis, type of water purification
ROB
Red open brain
RO/DI
Reverse osmosis, followed by deionization, type of water purification
ROFL
Rolling on the floor laughing
ROFLOL
Rolling on the floor laughing out loud
ROTFL
Rolling on the floor laughing
ROFLMAO/ROTFLMAO
Rolling on the floor laughing my *** off
ROTFLOL
Rolling on the floor laughing out loud
RR
Reef ready, aqaurium with pre-drilled holes and overflows
RTN
Rapid tissue necrosis
RUGF
Reverse flow undergravel filter
SAL
Salinity
"Saki"
Iwasaki, light manufacturer
SCWD
Switching Current Water Director, type of wave machine
SD
Southdown, type of sand
SE
Single ended, lighting designation
SG
Specific gravity
SHO
Super high output fluorescent light, equivalent to power compact fluorescent
Si
Silicon
SiO2
Silicon dioxide
SITD
Still in the dark
SO
Significant other
SPS
Small polyped Scleractinian (stoney) coral
Sr
Strontium
SW
Saltwater / seawater
TAR
Type of magnetic ballast / substance used to embed magnetic ballast coils
TBS
Tampa Bay Saltwater, mail order company
TFC
Thin film composite, type of RO membrane
TIA
Thanks in advance
TIC
Tongue in cheek
TM
Tropic Marin, manufacturer of fresh and saltwater products
TRT
The Reef Tank, aquarium bulletin board
TTYL
Talk to you later
TWP
Tap Water Purifier from Aquatic Pharmaceuticals
UGF
Undergravel filter
UV
Ultra violet, type of light of shorter wavelength than visible light
VHO
Very high output fluorescent light
W
Watts
WD ( W/D )
Wet dry, method of aquarium filtration
WPG
Watts per gallon, lighting quantity
WTF
What the F***
WTH
What the hell
WYSIWYG
What you see is what you get
X10
Automation/control products - Electronics mail order place
YMMV
Your mileage may vary