Sorry Hulton, I wrote a lengthy response to this post, but I must have failed at posting it
 
Here is an intake design I came up with that pulls water off the bottom of the tank. It wont be very pretty, but I designed it to be incorporated into a background for a drilled 30 gal I have
 
 
This is the layout I have planned for the 29 gal tank to be used as a sump on a 30 gal drilled tank The sand is a concept Ive yet to put into practice. But this will offer thorough mechanical filtration as well as biological filtration via a refugium. If you wanted to you could cut the refugium in half and use the other half for bio media
 
 
If you use two sumps on the same tank, youre going to want to tie them together. The simple way to do this is to connect a siphon between the two sumps.
 
Another approach you may want to consider, is to have the overflows flow into a container where it is offered thorough mechanical filtration and some bio (media or refug). Then have that container flow into a second container where it is further bio filtered (media & refug). To do this I would have the first container slightly higher than the second with bulkheads cut/drilled into the first container which will act as gravity fed overflows into the second container.