How often and how big of a water change?

I have a 55 gallon tank, I have 9 fish in it only one of them are a very big bioload hes a fantail goldfish. So I normally do a 25% water change once a week then every two weeks do two 25%. My other 20 gallon has 3 guppies I do 25%-50% every week on it. Should I be doing anything different? I haven't had any issues with my water but I was wondering what everyone else does?

 

That sounds like a pretty good water change schedule, but it all depends on how much food goes into the tanks. The best way to determine water changes is to test frequently (for nitrate if your tank is cycled). Then you'll know exactly whether your water changes are sufficient, rather than just guessing.

 

That sounds like a pretty good water change schedule, but it all depends on how much food goes into the tanks. The best way to determine water changes is to test frequently (for nitrate if your tank is cycled). Then you'll know exactly whether your water changes are sufficient, rather than just guessing.

I didnt know it but the test I had wasn't accurate for nitrites and nitrates. I got the master test kit a few weeks ago and my nitrates in the tank was 80ppm so I did a 50% water change instantly and got it down to under 20ppm it was just the old tank syndrome lol. I had never really heard of that term until after I looked it up. This tank has been running for at least 3 years so it's no wonder. There has been a LOT I have found out I didnt know. Thank god for the internet lol!

 

I have a very heavily stocked and planted 55 and I do a 50-75% WC every 5-7 days. I have a Fluval 406, An AC70 and a single corner and a dual sponge filter running in it. I would do 50% minimum especially having a goldfish in there.

 

I know its Iike having a goat in a tank lol they poop constantly! Do you think I should do two 25% a week instead of one big water change?

 

I do 50% once a week in my 55g.

 

I do 50% once a week in my 55 gallon.

Kk thank you