Sure. Let's see.
Protein skimmer plans: http://www.aquariacentral.com/forums/showthread.php?t=106781&highlight=diy+protein+skimmer
DIY refugium--may need more explanation. It is basically a separate container where water is fed to that is usually brightly illuminated to drive macroalgae growth. Good thread: http://www.aquariacentral.com/forums/showthread.php?t=130065&highlight=diy+refugium
DIY turf scrubber: http://www.aquariacentral.com/forums/showthread.php?t=161957&highlight=diy+refugium
DIY reactors: http://www.aquariacentral.com/forums/showthread.php?t=194730&highlight=diy+reactor
Those are just a few. Some quick searches will reveal more threads on these subjects.
Protein skimmer plans: http://www.aquariacentral.com/forums/showthread.php?t=106781&highlight=diy+protein+skimmer
DIY refugium--may need more explanation. It is basically a separate container where water is fed to that is usually brightly illuminated to drive macroalgae growth. Good thread: http://www.aquariacentral.com/forums/showthread.php?t=130065&highlight=diy+refugium
DIY turf scrubber: http://www.aquariacentral.com/forums/showthread.php?t=161957&highlight=diy+refugium
DIY reactors: http://www.aquariacentral.com/forums/showthread.php?t=194730&highlight=diy+reactor
Those are just a few. Some quick searches will reveal more threads on these subjects.