When Should I Do A Water Change?

Ioana Dog

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When I have even slight ammonia (starting at 0.25 or I can’t tell for sure) I do a water change - 30% for 0.25 and 50% for 0.5 or more). I do the same for nitrites. When should I be doing changes? Can you do too many water changes?

I think I’m over feeding or I have fish tank OCD because if there is visible food left over an hour after feeding I vacuum (I have black sand so I can see where the food and poop are).

Thank you!!!!
 

Eirelav_mcgoo

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If you're monitoring your levels, water changes should be done when you nitrates get above 40ppm, depending on your source water. Waiting till your tank reads an ammonia level means the bacteria is outpaced by the waste. It will negatively impact your fish and your cycle.

Most people perform weekly water changes, but it depends on your filtration and your stock. I am heavily stocked and my filtration just barely does the job, so I do one or two water changes a week (depends if I've been feeding or my boyfriend has been feeding lol). I also test my water every couple days, if nitrates get over 40ppm, I do a 30% water change.
 
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Ioana Dog

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I monitor the values daily because they just completed cycling a few weeks ago then I continue to monitor after I add more fish (slowly stocking them). I usually see a slight ammonia and/or nitrite spike after I add fish but it only last a day or two. When everyone hung is back to normal for a couple days I add a few more fish. Can I do too many water changes?
 

Eirelav_mcgoo

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I've read members say too many water changes can hurt your cycle.

If you're cycled, then I would be changing the water based on nitrate levels, not ammonia and nitrite. Unless there's a spike or your losing the cycle
 

Fashooga

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If your tank is well established, like 6+ months you should be doing a weekly water change.

If you tend to overfeed your fish you might want to consider 2 water changes a week. Or you can reduce the amount of food you put in. I feed my fish once a day and don’t feed them on weekends.

There are a lot of people who do a lot of water changes per week but it depends on the situation. A smaller tank requires more maintenance due to its size...hence more water changes.

Larger tanks requires less work but still require weekly, bi weekly water changes. Larger tanks are easier because the volume of the tank.
 

TexasDomer

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I don't think you can really do too many water changes. It sounds like you're handling it well! Once the tank is fully cycled (no ammonia and no nitrates), you can back off to weekly changes of 30-50% or so. If nitrates are above 40 ppm even with this, you can reduce your stocking or do more frequent changes.
 
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