Originally Posted by rodneyri
the LFS suggested today that i get a tank with two holes in the back of the tank for the syphon and return plumbing rather than an overflow system and holes in the base.
is there any advantage of either, which is preferred?
Yes, there is a big difference. with the holes at the top rear of the tank, you are able to install a "Coast to Coast" overflow system, also commonly referred to as a "Calfo Overflo" (care to give a guess on the mind behind this innovation?)
The coast to coast is by far the best overflow option. The Calfo overflow has far superior surface skimming efficiency, is far quieter than conventional overflow systems, and is much more aesthetically pleasing. The only downfall to these overflow systems is that they are not practical in long, narrow tanks.