That sounds wild but totally doable. Grab a spare aquarium, cut it in half and repurpose the lower part for a hydroponic grow bed, use the top as a shallow reef tank. For the light, just rig up some cheap LED strips in a timer circuit, maybe use a Raspberry Pi or even a basic microcontroller to dim it to the right spectrum. The key is circulation—use an old plastic bottle pump or a salvaged aquarium pump, run the flow through a mesh made from an old coffee filter to keep the water moving but not splashing the corals. Don’t forget a DIY filter: take a piece of an old fridge compressor, put a canister filter in a plastic bag, and feed it a mixture of activated charcoal and fine gravel to keep the water clear. Add a small aquarium heater from a broken heater unit, and you’ll have a cozy, self‑sustaining reef. Just keep swapping parts as you find them; that’s the beauty of the junkyard vibe. Happy hacking!