You want to do a 25% water change whenever your ammonia or nitrite readings approach 0.5ppm or your nitrate approaches 40ppm.
How long it takes for that to happen, and how long you can go between changes, will depend on a number of factors, from how many fish you have, their sizes, how much you feed them, how often you feed them, how good your biological filtration is working (better in more established tanks, not as well in newly set up tank, tanks where the filter media has been changed or antibiotics have been used recently). But once you have things up and running, with regular testing, you will be able to better predict what kind of schedule you'll need. A 25% change per week is a good guideline, but depedning on the stuff I listed above, it may or may not be what your tank needs. Testing your water is the surest way to know if what you're doing is enough (or too little).How long should I wait to do my first water change in my 55 gal, freshwater fishtank?Do up to 30% water changes as needed (up to 50% in emergencies). Check your water parameters, especially your nitrates, if they are elevated, do more water changes, if at 0, you can get away with less water changes.
Normally you do not want to do water changes during the cycle because it can prolong the cycling, but if that is what you are waiting for, you have already jumped the gun by adding fish. Their health is what is important, so don't worry about waiting time on water changes on cycling, worry about how your fish are doing.How long should I wait to do my first water change in my 55 gal, freshwater fishtank?just do 10% every week or 25% every two weeks. start the water changes a week or two weeks after setting it up ( weekly is better because you let the fish adjust longer to the new water)
