Well, because TFF is based out of the UK, members from there will use the metric system. I don't mean to offend anyone, but rather than complain about it, take this as a unique opportunity to learn the metric system, especially if you're in school. You have converters in a pinned topic, why not use your hobby as an excuse to learn the new system. We'll have to probably learn it eventually, so why not just start with your hobby. Though I agree, the US will officially convert only after decades of kicking, screaming, and foot dragging, probably when I am long dead and buried.
It's like learning a language. You start by learning the rules of grammar and the meanings of words, and at first you translate them in your head. So, at first, you'll learn the formulas of conversion and the units in the metric system and you'll whip our your trusty calculator to do conversions. Then you'll progress to being able to do conversions between the two systems in your head. Eventually, with time, you'll start to think in the new system. I'm not saying it's quick, but for goodness sake, if illiterate street vendors in India can learn the system without much effort, according to a post way back in this thread, we can learn this system, which is far superior to the US system. Sorry, but I really feel this way, and I'm as American as they come!
Though I haven't fully converted yet, it is so much easier to dose meds and ferts using metric units rather than gallons or the perrenial "cap full". This thread is making me want to fully convert, though.
A great way to start is with your thermometer, many come with degrees in both Farenheit (sp) and Celsius
Sorry, if I've offended anyone, but this is just how I feel about this subject.