hey john and welcome to the little ocean.
This forum is a a little slow at times so sorry for any delays...I still hold out hope that this forum will turn into something a little more popular and busy... but until then...
as for your tank, congrats... and yes, smaller tanks have different propblems that will keep you on your toes... meaning, things happen fast... and usually for corals, things that happen fast are usually not good... but moving on.
things to look out for in a smaller tank is water evaperation... when water evaporates, ONLY the fresh water evaps, not salt... so what happens is the wter turns more salty, *(higher salinity)... so for smaller tanks, salinity is what will be the variable... and again, changes arent good for coral growth.. and in more extreme cases, leads to coral death. and failure.
the problems with bigger tanks are 1, when things happen, it usually affects more organisms.. which means more money at risk...
but, larger tanks also have issues with utuility costs... electricity to operate the lights, and then in the summer to cool the water due to the heat generated by the lights...
anyways... you have a lot to read and ask, and this is a great forum to do that... btw, there are a couple other canucks on this forum, and i am sure they will pop up shortly... hehehe
let us know what equipment you have already, filters, lights, test kits, etc... also let us know what goals you have, what organisms you want to keep, and also, what local fish stores you ahve near you... what type of selection do they have...