They're rip offs! Lol I made my own with a proper nice hose for 15$ and a gardening two way valve. What I like about the garden hose it expands when water is in it and constricts when not in use. Makes storing the hose so much easier.I'd suggest testing the water on a regular basis. You want to change the water when nitrates get to about 20, maybe a bit higher depending on the fish. Weekly is a decent bet.
If it's a lot of effort, get a Python water changer. Makes things a lot easier.