Since there are so many abbreviations in this hobby, it is sometimes confusing. So I'll list the ones I use:
| :D | Big Grin |
| AFAIK | As Far As I Know |
| Alk | Alkalinity |
| BB | Bulletin Board |
| brb | Be Right Back |
| bbl | Be Back Later |
| BTW | By The Way |
| Ca | Calcium |
| Ca(OH)2 | Limewater (kalkwasser) |
| CO2 | Carbon Dioxide |
| Cyano | Cyanobacteria (red slime algae) |
| DI | De-Ionised (water) |
| DOC | Dissolved Organic Carbon (Organics) |
| DSB | Deep Sand Bed |
| FOWLR | Fish Only With Live Rock (Aquarium) |
| FUBAR | F'd Up Beyond All Recognition |
| FWIW | For What Its Worth |
| FYI | For Your Information |
| HTH | Hope That Helps |
| IIRC | If I Recall Correctly |
| IME | In My Experience |
| IMHO | In My Humble Opinion |
| IMO | In My Opinion |
| IOW | In Other Words |
| IRC | Internet Relay Chat |
| JMO | Just My Opinion |
| k | OK |
| Kalk | Kalkwasser (Limewater – Ca(OH)2 solution) |
| LFS | Local Fish Store |
| LOL | Lots Of Laughs or Laughing Out Loud |
| LPS | Long Polyped Stony coral |
| LR | Live Rock |
| LS | Live Sand |
| Mg | Magnesium |
| MO | Mail Order |
| NO | Normal Output (430mA) fluorescent tube |
| NO2 | Nitrite |
| NO3 | Nitrate |
| np | No Problem |
| PAR | Photosynthetically Available Radiation (useful light to the coral) |
| PC | Power Compact fluorescent tube |
| PITA | Pain In The Ass (Arse) |
| prolly | Probably |
| RO | Reverse Osmosis |
| ROFL | Rolling On the Floor Laughing |
| ROFLMAO | Rolling On the Floor Laughing My Ass (arse) Off |
| SG | Specific Gravity (Salinity) |
| SPS | Short Polyped Stony coral |
| TIA | Thanks In Advance |
| TTYL | Talk To You Later |
| VHO | Very High Output (1500mA) fluorescent tube |
| YMMV | Your Mileage May Vary |