Solve 80% Of Aquarium Problems

What if there was one medicine that solved 80% of all illnesses in the world.

That would be pretty amazing. Well in the saltwater aquarium world, there is something that does that. Weekly water changes. I'm not saying it will cure 80% of everything, but it will prevent 80% of the bad things from ever happening.

Why water changes are a secret weapon, how to perform a perfect water change, choosing the right salt, and common aquarium issues that can be solved with a weekly water change.