Saltwater to Freshwater?

What are the steps that one would need to take to transform a saltwater tank into a freshwater tank? How would I go about cleaning it before use?
Answers:
What you'll need to do will depend a little on the material the tank is made of and the types of freshwater fish you plan to keep.
As far as the substrate, this is probably a crushed coral or shell material. This would be okay to rinse off through a strainer under hot water and reuse if your planned fish are African cichlids, or other species that need a higher pH. If you're not planning to keep any of these, I would suggest changing to standard aquarium gravel or sand, depending on the needs of your fish and your preferences.
You'll mosy likely need to clean the walls of the tank, and if these are glass, you can use a standard algae scraper and vinegar and hot water to remove any coralline algae or tube worms that have attached to the glass. If there are stubborn spots, you might need to use a razor to scrape them off. Be aware if the glass itself looks cloudy, there may have been permanent etching from the high pH - this won't be something you're able to get rid of, because the glass itself has become pitted. It doesn't look quite as bad when the tank has water in it, but it may still be noticeable. If the tank is acrylic, you'll need to be more careful about cleaning the walls, because this is more likely to be scratched. Use the hot water still, but use either a pad made for cleaning acrylic, and be sure no particles of the substrate get causght between the pad and the tank surface, or use the edge of an old plastic card (credit card type) to scrape.
If there are heaters, powerheads, or filters that were for the tank, these should be able to be used as well, just clean with hot water and use vinegar to remove salt build-up.
Other than these specifics, everything else would be the same as setting up a freshwater tank from scratch.

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well, you'd really have to be careful because if any remains of salt could kill your fish. really have a good couple of goes at the walls, the filtres, just about everything that was in your tank. may even be a good idea to wipe the light (the plastic covering it)
swish hot water in there aswell. add some water purer for fresh water fish in aswell.
after that you should be fine

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Not much to worry about here. Remove any gravel/ sand or filter media you were using in the saltwater aquarium as this will hold large concentrations of salt. Some salt is ok for most freshwater fish and even suggested.
To remove the calcerous algeas on the tank low concentrations of vinegar are helpful, but they can be scraped off with a little elbow grease. BUt this does not need to be removed.
Remeber you will need to recycle the tank as different bacteria live in freshwater when compared to salt.