right now i have a 90 but eventually know a upgrade is inevitable. say maybe a 180 or 240? any ways. i want to make a skimmer that is 10" or 12" in diameter. what is the shortest height i can make it and still have it be efficient in removing proteins. what umps would you recomend and where is the best place online to order acrylic tube without having to get 5 or 6 feet?