# What % of water do I change?



## MSDdivers (Nov 24, 2014)

From what I can see on this forum, fish keepers change anywhere from twenty-five to sixty present of the tank water per week.

In my 104 gallon tank, I will have twenty Malawi Cichlids, three inch average in size, two catfish.

What percentage of water would you change and how often?


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## Frank-the-tank (Sep 28, 2014)

I the average I've seen is 40% once a week.


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## workharddieproud (Nov 7, 2013)

I average changing about 25G to 50G in my 125G, anywhere from 5 to 8 days, just depends on my schedule and feeding habits and my mood. I certainly wouldn't go over 10 days without a water change. But I concentrate more on getting the junk cleaned up Vs. how much water I'm sucking out.


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## DJRansome (Oct 29, 2005)

50% weekly and then check to see your nitrate is <= 20ppm. If your nitrate gets higher than 20ppm then up the % of your water changes.


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## BDASTRK (Dec 12, 2014)

I would ALWAYS do a study on the Nitrate levels of your tank for 4 strait months, once you determine the nitrite levels and the water change % starting at 20% of the total volume of the tank and work your way up you will create a water change schedule. Now adding and subtracting fish come in to play once you start a schedule but as a whole I can tell you that I change 2 times a week, Every Wednesday and Sunday and the quantity is 25% with 76 fish in the 135. All of my fish are from 3" to 8"................But all set-ups will be different of coarse.


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## Austinite (Jul 27, 2013)

I change close to 50% of the water every week. I don't skip a week ever. I also test each week for nitrates, and this alerts me early to any potential problems. Whenever I see an issue with a fish like a scrape, white spot or anything unusual, I start changing my water almost daily until the ailment goes away. And it works just about every time. I think it's the most important thing you can do for your tank is frequent water changes.


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## jw85 (Dec 24, 2013)

Agree with Austine. I change out 54 gallons from my 125 twice a week, until my nitrates start to creep up, then I'll do changes daily for like 3-4 days to get it down.

I'd say on top of figuring out a regular schedule, you need a plan for what to do when your nitrates eventually creep up. Even if you do 90% once a week, eventually you get nitrate creep if you are always consistent.


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## plug (Nov 10, 2013)

I do 40 -50% water changes twice a week in my 125 Tank
I also check the nitrate levels before each change and this tells me when the nitrates are up so I get on the water changes


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## charlesc (Aug 19, 2013)

I change between 50% to 80% on my mbuna tanks. When my work schedule allows I do water changes every week.


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## Razzo (Oct 17, 2007)

In my 72-gallon tank, my water change is approx. 40 gallons. I have a lot of big rocks in my tank; so, if I conservatively allow 5 gallons of water displacement from the rocks & sand, my 72 gallon tanks holds about 67 actual gallons of water. That 40 gallons of new water would equate to a 60% water change. Nitrate levels are around 10ppm.

Weekly water changes.


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## Rare7 (Dec 31, 2014)

I do 50% to 60% on the 130g. I do this every week to replenish the mineral that are gone with new water. I don't test, fish tells me whats going on & there is many more thing that we cant even test that doing PWC every week is a good thing. Even when nitrate were low in my aquarium when i used to test for them every week, they were in the 20ppm zone. I changes the filter twice a week om the wet/dry. On the 3rd week i do a deep cleaning. With a fish net and filter sock plus a bucket. The net catches the bigger stuff and the filter socks catching the finer things. The bucket has a bulk fitting with a PVC pipe that water goes right back into the sump. This way i can take my time to clean all around & not worrying if i have enough time before water is running low.


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## jlose600 (Aug 6, 2012)

I do two 50% water changes a week. My nitrates have never been above 10ppm!!


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