Have you cycled your tank? It depends on your setup and water quality. I siphon and net up up poop and dirt daily with a turkey baster and small fish net, and test my water once a week. If tank levels all test fine, I just do a 10-25% water change once a week or so to replace water that’s evaporated or removed in siphoning.
To test water levels I use an API fresh water test for PH, nitrites and nitrates and a Seachem ammonia test to check the free ammonia levels. (The API test only test for total ammonia.) Hope this helps, and welcome to the wild world of axolotls!
