The word "pool" is more likely coming from using an on-line dictionary/translator. You have to be really careful and pay attention to what words you use and how you say things when talking to people in other countries who may speak little or no English. Using slang words like "tank" instead of "aquarium" usually result in words like "pool" or "basin" being returned by the software.
Similarly, I notice an almost complete lack of understanding or willingness to use correct grammar and spelling on the forums by many members. Use a spell-checker. I imagine many statements made here will turn out as total gibberish by translator software in other countries.
Use simple, correct words and avoid cultural idioms that do not translate when speaking with people in non-English speaking countries to gain the best degree of communication.
Dave.M