
The black mark indicates plugs. Plugging off and allowing only 2 clear passage for the water. The top adapters are both 1/2" barb, which will have vinyl tubing that will attached to the eheim intake pipe to go into the eheim canisters. I will have 2 different return, one on the water surface and one all the way at bottom, to help water circulation.
The other idea I had in my was use the red as intake to the Eheim then the green tube for outtake back into the tank. Not sure which is best yet, will have to do some testing in my tank during the next full cleaning.
I bought some silicone to glue the Slate rock to the egg crate that will be sitting ontop but it didn't smell right. GE Silicone II claims to be 100% silicone, but the 100% silicone I've used previously smells like vinegar smacked you in the face. This one smell a slight bit like glue. I'll have to go back and purchase a new tube.
I was thinking about using slate tiles to go across bottom and possibly the side, it will make it aesthetically more pleasing and give the turtles a nice little cave to hide in. but that will have to wait until testing is done.