I wish I'd had vinegar in stock when I cleaned this tank. I have since purchased a new jug of fish tank cleaner, aka "vinegar". Pff. Like there's any other reason I'd buy vinegar. MTS SUPPORTS MASS VINEGAR PRODUCTION!!!
Vinegar for sure. I inheirited a 55g acrylic that was used for saltwater. filled it for leak testing and added a gallon of white vinegar, let it sit overnight then drained it and wiped it down. All the deposits came off with no real labor.