Apex Jr ?

[fooman]

First I would like to say hello to everyone and thanks for all the great reading and tips. Okay hear we go I have a 150 gallon DT and a 100 gallon sump and run a curve 9 skimmer. I am thinking of getting an Apex and don't really have the cash for the more expensive one but I see there is a Jr Apex that looks like it might work for me . I am wondering if I go ahead and get the Jr can I slowly up grade it to the full Apex ? I know it will cost more in the long run if I can but that is the only way I can go about doing it.