How do I clean used aquarium substrate.

[Joshuakahan]

Our tanks may never come in first place but we make a great number two!

I’m thinking about a drip system from my septic tank to my fish tank

 

[duanes]

I personally would trash the substrate and replace with new.

Agree
You never know if the previous owners fish were diseased, and its common for some pathogenic bacteria to go dormant for years, and reanimate once hydrated.