Hey kinkfish. Water changes should definatly be performed on a regular basis. It replaces trace elements, removes waste, dilutes heavy metals from the food we add. There is some people that do not advocate doing waterchanges. Why they choose to do so is beyond me. Salt is cheap and can combat alot of issues that a hobbiest simply can not test for. It is best to match the SG and temp and Ph to the same parameters as your tank so it does not shock your system. Small and frequent water changes seem to be the best. Its best to find a routine that works for you.