The Cutting
 Trying to make the best use of the 21 X 18 inch footprint
 inside the tank I decided to design an external overflow
system to allow great surface skimming and take up virtually none
of my precious real-estate inside the tank.
I carefully cut away the trim portion of the Oceanic top rail
leaving the "meat" on the top edge 


 

The Setup
To provide as much strength as possible while still allowing more
 flow than the calculated requirement for the return.
 I decided to drill (5) 1" holes to provide spillover into the overflow.
I marked out the hole locations and formed dams of plumbers putty
 around each hole to contain the cooling water
required to keep the diamond hole-saw free of glass
dust and cool as it ground it's way thru the tank wall

 

The Drilling
I made use of an older tabletop drill press that my father had left
in my care when he moved to his apartment.
I set the speed at 650 RPM
I placed the tank on top of 2" of DOW pink board
insulation to provide some cushion
 in the event I got carried away with bit pressure.
I turned it on,  held my breath and plunged in.

Finished Drilling
Here is the finished product just after drilling
The 3/4 bulkheads are for the returns to the bottom of the tank


 

Attached The External Overflow Box
I constructed this overflow box using 1/4 " glass
I drilled a hole for a 1" bulkhead fitting in the bottom plate
I used 100% silicone to attach the box to the tank back
I am still working on the plumbing for the return
the design shown was loud and created millions of bubbles
in the sump


Plumbing The Ocean Motion Squirt 2 Way

The OM Squirt 2 way was added using unions on the inlet
and the outlets in case service is needed