The eggcrate is cut to fit the bottom of the tank, leaving some space at one end for a water portion. The area covered by the eggcrate will be the land portion. The PVC sections can be glued to the underside of the eggcrate to raise it up, or they can be attached by tying them on with nylon cable ties.  In this tank's case, a well was cut in the eggcrate in one corner opposite the water portion, to allow a water pump to be inserted.

 



    The use of false bottoms is one way to provide drainage to a vivarium without the trouble of drilling a drainage hole, or using heavy materials like gravel. It also allows water to circulate freely under the substrate, distributing heat and nutrients to the plant's roots. 

    Materials needed for the platform are: plastic eggcrate (a stiff plastic grid used as a diffuser in lighting fixtures; available at hardware stores), plastic needlepoint mesh (available at craft stores), fiberglass window screen, and sections of PVC pipe. The diameter of the pipe is determined by how high you want to elevate the eggcrate platform. 





 Window screen installation

 

This pump will draw water from under the false bottom, and send it to the water portion on the other side of the tank, thereby ensuring that the water circulates under the substrate. 
Top view: Aliflor layer
      The Aliflor is covered with more window screen then topped with a planting mix developed by the Atlanta Botanical Gardens. More cork bark is used to build up different levels of the planting mix. The mix is then wet down and the water pump installed in the well.
Top view: Planting mix layer
      If desired, the water pump may be covered with gravel, or a nontoxic synthetic sponge can be cut to size and stuffed into the well on top of the pump. This is to prevent animals from getting trapped in the well. The tank is then wet down and the water section filled to the level of the Aliflor. Once everything is tested and in good running order, plants can be put in and allowed to establish themselves. 
      A cork slab is used to build a waterfall, and water is sent by the pump, up a pipe and to the cork bark. From there it drips down, collects in the water portion, passes under the substrate and back to the pump in the well.  This allows heated water and nutrients (from frog waste, washed down through the substrate) to be distributed throughout the tank, and at the same time prevent the planting mix from becoming soggy. 
The PVC platform
Copyright 1999
by David North and
Kenneth K. Uy.
All rights reserved.
     The plastic needlepoint mesh is used to build a slope from the eggcrate to the bottom of the tank. The eggcrate and needlepoint mesh is then covered by fiberglass window screen to prevent substrate from falling into the false bottom. The window screen is then topped with the substrate; in this case it is Aliflor, a lightweight expanded clay aggregate used in hydroponics gardening. The Aliflor is separated from the water portion and well using sections of cork bark. 

ATLANTA BOTANICAL GARDENS PLANTING MIX

2 parts fine fir bark
2 parts fine tree fern fiber
2 parts milled sphagnum moss
1 part fine charcoal
1 part peat moss

Completed tank