How often would I need to change the water for a 20 gallon aquarium with 10 small fish?

Question

How often would I need to change the water for a 20 gallon aquarium with 10 small fish?

Answer 1

Yeah.. it depends on the chemicals and how well established your tank is maintained. Buy those 6 in one testing strips and test your water once a week.

It does depend on you water quality, but if it is good and you have good filtration you can do 20% about once a month.

Answer 2

The simple answer is 20-25% once a week. The smaller the tank the harder it is to keep stable. You need to get a good test kit, I recommend API liquid master test kit. It is a bit expensive but last for a long time and is way more accurate then the strips.

If you have live plants then the nitrate level will be of more concern because they need nitrate. If not then you should only have to worry when they get above 20pmm but a once a week water change should take care of that.  

Answer 3

maybe once a week?  

Answer 4

The answer has too many variables that is based on what your water quality is like at the time of water change. If the water quality shows little to no nitrates, then a 10 percent water change a month is sufficient. If the nitrates are higher, then of course a larger amount of water needs to be changed out more often to dilute the nitrates . Simply doing a water change will not dilute your nitrates by the same amount. Meaning if your nitrates were lets say at 100 mg/l , changing 25% will not drop it down 25%. Numerous water changes will need to be made to simply dilute the nitrates enough to be within acceptible range. Also, if you have a lot of debris that hits your substrate such as plant matter, algae, fecal matter, this all will have to be removed before it breaks down and becomes a part of your nitrate issue.