It probably wont make a difference, but changing it once a week will be much less work.
Water changes are never bad for your fish, so if you want to change it every day, have a ball. But in a properly filtered tank that is fully cycled, you should not need to do water changes more than once a week, and even then only 25% or 30% of the water.
If you are worried about water quality, augment your biological filter by adding live plants and additional filter media for your bacterial colony to live on - http://www.exoticgoldfish.net/care.html# -. The larger the surface area of the media, the more benign bacteria you will be able to sustain. Both the plants and the bacteria will eat the bad stuff in your tank, like Ammonia, Nitrites and Nitrates.
Larger tanks tend to be more chemically stable. While water changes are important for all aquariums, they are more important for smaller ones than for larger ones. And a 55 is a pretty good size.For a 55-g tank (goldfish), is it better changing 4 g/day everyday or 28 g once every week? Any differences?Sounds like a lot of work, doing it everyd ay. but if that's what you want to do? As long as you have excellent filtration, weekly partial water changes are fine.For a 55-g tank (goldfish), is it better changing 4 g/day everyday or 28 g once every week? Any differences?I think it would be better to go weekly, possibly bi-weekly if it is very dirty.
The reason why is because if you have to clean in everyday it will be cumbersome and you might not put as much effort into it, like vacuming and scrapping.
The key is get all the poop and excess food out. And to balance the water properly.
If you are constantly changing up the parameters it might be too stressful on you and your fish.
