for three main reasons, one because all my equipment is used and were given to me ether broken or bad conditions, so my 70G is acrylic and cratched up bad, and my 55G is the only desent one i have for displays, second if i were to setup the 70G i will need more lightthing, and right now i have a 400Watts MH on the 55G, and third because im currectly financial uncapable. i wish i could get new equipment and such but at the momnet i cant.