That’s awesome thank you so much for letting us show your skills! Very creative love that idea I’m gonna try that on my backyard I have that perfect space for it.
The lava rock and strange looking cylinders in the 2 identical bowls is the same stuff used in canister filters. The high surface area contains bacteria that break down the ammonia into nitrites then nitrates. At that point you can/will grow algae and/or plants on the nitrates, or just do regular water changes to keep nitrates in check.
Additional informations and steps are required: * What was that tree he chomped and why ? * What kind of rocks and things he added in the pots and why ? Why not hide the water pump it ruined the whole look? Paint the grey pipes to terracotta colour maybe ? Amazing handcraft nonetheless
The rocks he added to the pots provide a large surface area for bacterial growth. Nitrogen fixing bacteria will grow on those stones and absorb the fish waste dissolved in the water, ammonia mostly. They will consume this harmful waste and change it to less toxic nitrate, cleaning the aquarium, and providing food for aquatic plants. The circle of life.
The water will become alkaline in contact with the mortar. The fish will die. Neutralize the mortar with muriatic acid after it is cured (30 days), and rinse multiple times before adding fish.
