Step 2: Water circulation

The circulation system consists of dripping pipes supplied by four 12vdc submersible pumps, and some colIecting pipe for sending water back to the fish in tank.
I drilled 4mm holes in the drip pipes to permit pass throught water and bigger holes in the   collecting pipe  accommodate the bottlenecks. Some connections between pipes are made with water hoses.
three pumps take water from the filter that is connected to the fish tank,  the other from rain barrels placed on the east side of the building. In this way, i try to compensate for the water lost to evapo-transpiration, soil absorption and any  little losses of the circulation , without having to refill it manually.
In the south side, after crossing the planters, the excess water is collected and conveyed to the drip pipe below and from there through the planters arrive in the fish tank. In the  west side, after passing through 2 rows of stacked planters, water flows through "the  green window" of  sedum plants and then passes into the main collecting pipe and in the fish tank. After passing into the bio filter, the water begins a new cycle.