I have take inspiration from this thread to make a pipe
fuge of my own. I have a BC8 in my bedroom so space is a little tight. I don't have the room for a congenital
fuge. So, when I saw the video I was struck by the intense desire to smell
PVC glue.
This is what I came up with:

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The parts list is:
38" of 4" dia
PVC pipe
1 4"
PVC cap
1 4"
PVC Closet (toilet) flange
1 4"
PVC clean out adapter with plug
1 1/2
PVC slip to female pipe thread adapter
1 1/2 plastic male pipe thread to male hose barb
1 1/2 plastic hose barb 90 deg. elbow
10' clear nylon hose
Here it is:

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This is my
fuge installed and running:

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The total volume is a little over 2 gallons. I put about 10# of rock inside. 2# live and 8# base.
I also modded the hood to allow for a clean install of the hoses.
Now all I need to do is monitor my
nitrates and watch them drop down to nothing.