Yesterday have filled the buckets with water and waited until today for chlorine to dissipate. Walstad suggests to put 1.5″ of soil and 1.5″ of gravel in the tank. A hobbyist with a Walstad aquarium in a forum set up her tank with pond soil, so I followed her example. The pond soil I got does not contain chemical fertilisers and has pieces of clay in it. Walstad says about clay:
Clay has 10,000 times more surface area than sand, which gives clay a much greater capacity to bind plant nutrients than sand. Thus, only clay and humus, not sand or silt, contribute significantly to a soil’s cation-binding capacity.
Soil binding of cation keeps substrate nutrients from entering water. Indeed, soil particles can even pull nutrients like copper out of the overlying water.
I did not even have to sieve out any wood pieces as Foo the Flowerhorn did, because the pond soil contained very few of them—and by sieving I would remove all the valuable clay globlets.
After 1.5″ of pond soil were in the aquarium, I sprayed it with water, watching how it gets moist, wet, and ultimately started building puddles of water. It took a while to spray about 3 litres of water on it, but it was fun to watch.
Within minutes the soil started releasing bubbles and sink to about 1″.
The gravel came next. Walstad suggests 1.5″ thick and Foo the Flowerhorn reports that the soil substrate eventually rise into the gravel, so while 1.5″ may seem too much at first, it should turn out just the right amount. The gravel cap compresses the soil a bit.
Then came the big moment. First water. Like the First Light moment for a telescope, First Water for an aquarium is a one-in-a-lifetime occasion. It feels like imbuing it with life. Of course none of it is apparent yet, but I imagined all the tiny microbes and micro-organisms in the soil awaking from their deep sleep and already staring their work.
Now I want to give it two days rest. I may poke around in the gravel cap a bit tomorrow to release the bubbles like Foo did, then let is rest for yet another day.
A drop of water, if it could write out its own history, would explain the universe to us. — Lucy Larcom