I think you may be out of luck on this one.  The Oceanic 150 trickle filter was one of the Plus series of Trickle filters that Oceanic discontinued more than 10 years ago.  They were replaced by the Oceanic sumps.  Even back then there were not instruction manuals for the filters (which is actually typical of wet/dry filters) as these systems are often sold incomplete and can be setup a number of different ways by the end user.  I just got rid of my Oceanic 300 trickle filter at the Fall swap.  I think I gave it to Jeff.  It's larger but the design is similar.  The water from your overflow boxes drains into the filter through two bulkhead fittings connected to the glass lid.  The water goes into a chamber in the back center of the filter that fills and then overflows onto the drip tray.  A submersible pump (not included with the filter) would go in the front right corner of the filter and connect up to pvc pipe or tubing to pump the water back to your returns.  There is also a bulkhead fitting on the side for hooking up an external pump if you wanted.
 
It's kind of hard to explain all this in a forum post but if you need help let me know.
Andy

I would use an Aqueon 4000 submersible pump myself.  They are quiet, reliable, and energy efficient.  But I am not that impartial.  Mag Drive's are also good pumps.  A Mag drive #950 or #12 is a good alternative but is not as energy efficient.
Andy

Ha Ha I wish!  
Have you given any thoughts on how you would plumb the return?
the simplest would be to connect some 3/4" ID tubing to the outlet of the pump up to a T fitting and from there run the 3/4" up to the returns on the tank.  
The most complex would be to run 3/4" pipe up to a check valve, union, T fitting, and then 2 ball valves (one on each side of the T fitting).  This gives you better overflow protection during a power outage and you can adjust the water flow between each side evenly.  You may also want to go up to 1" pvc pipe so you can get more water flow.
 
Andy

GOT ALL THE PLUMBING DONE. WAITING ON THE BACKGROUND.I HAVE A ? ABOUT HEATING THIS 135 GALLON TANK.
IF I PUT THE HEATER IN THE SUMP WHAT WATT HEATER SHOULD I USE?

When I ran my 135 gallon with a sump, I placed a 500 W titanium heater in the sump and the thermostat in the tank.  One thing you really have to be careful about with this setup is during water changes.  If you don't turn down the heater when the thermostat is out of the water  the water in the sump will overheat.  When you fill the tank back up and turn on the sump pump again you can pump hot water into the tank.  I did this one time, and it was not pretty.  The other issue is of course forgetting to turn the heater back up, which we have all done I am sure.   One solution is to put the thermostat in the sump, but I don't like that setup since the tank is what needs the heat regulation.  However you set this up, putting the heater in the sump will make your tank look better and avoids the need to hide wires and what not.  Just my 2 cents.