do you have to remove any water after you have a maintained saltwater tank?

Answer 1

Water changes are necessary in any aquarium. It will be more expensive in a saltwater tank because you have to purchase special salt for the marine fish. The water must also be tested for salinity because you must get it right for marine fish to stay healthy. I believe it should be 1.025 on a salinity tester. Freshwater tests at 1.000. Not much different, eh? But it slowly kills the fish if it isn't right on.

Fish waste, uneaten food and various debris from plants will all decay into ammonia, nitrites and nitrates. Filters do not remove these chemicals and they are all toxic to your fish.

Weekly, 30-40% water changes must be done to maintain a stable healthy water quality. If not done, the ammonia (which is the most toxic) will build up to the point where it actually burns the gills of the fish. They slowly suffocate as the gills do not regenerate like other tissue.

Answer 2

Short answer, yes.

Long answer, there is a relationship between water volume and time between water changes. A 5 gallon tank will require a water change much sooner than a 5000 gallon tank. As well, depending on the number and types of fish you have and the whether or not you have anything in the tank that aids in cleansing can alter the need to change the water.

Do you have live rock? Filter fish such as shrimp or duster worms? If not, you may have to change the water more often.