Here is a simple drainage system I constructed for a two piece China cabinet conversion.
I sawed through the top and bottom cabinet and cut into the divider walls to allow the draining basin to sit as deep as possible without interfering with the cabinet/drawer access below. It required a few difficult angles with various saw tools to get it level but it is not too bad if you take your time with it or have the correct tool, which I did not. I then made a custom catch basin out of used scrap wood since I found it a little easier to work with than acrylic or other such materials.
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The interior got lined with a few layers of silicone and then I gave it a thorough water test to make sure there were no leaks. I put a drain bulkhead in the bottom and cut it down just a bit to allow a slightly lower water level inside the basin.
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The outflow hose is just acrylic tubing attached to an irrigation shutoff valve hanging over a 5 gallon bucket. I cut down some pool noodles to use as a rain skirt to transition water from the background walls of the vivarium into the drainage basin.
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It was fairly simple to cut and apply the formed foam and secure it in place with more silicone. You should allow just enough overhang to allow for a proper drip line into the catch basin especially if working with wood structures to prevent serious water damage if there is a leak. I used clay pebbles under a screen separator and then substrate on top.
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I run another 5 gal R.O. from the other side of the cabinet which ties into a MistKing pump/ 8 nozzle spray system. So far it has been a very simple and effective design and would not be too difficult to tweak and apply to many different applications.
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