Natural ways to clean tank

The biggest natural method to clean the tank, substrate, plants, or even any decorations would be to use white vinegar. It's natural, actually pretty cheap compared to other cleaners, and it won't be harmful if some is accidentally left inside when you put the fish back in (unlike bleach which requires HEAVY cleaning and verification that there is none left, otherwise in small traces it is fatal).

Vinegar, using good old elbow grease is probably the best. Sponges work, and if the dirt or grime is bad even trying to use hot water + a pocket knife to not scratch the glass but remove anything tough sticking on it (from my last lovely experience when I bought a used tank with horrible calcium stains all over).

Sent from my iPhone using Tapatalk

The best natural ingredient are the vinegar and salt which will remove any hard water stains and fishy smells. But make sure that you thoroughly rinse and clean an then fill up with water.