# Keep up with weekly or bi-weekly water changes?



## cmarti (Feb 26, 2010)

Hi all,
I have a 55 gallon freshwater, no real plants, just a crapload of fake ones. I have between 20-25 fish in it, mostly different types of tetras, a gourami, an angelfish, 2 cory's 1 catfish, and a small koi (I know it's small for a koi, but the koi was a present, but when it gets a little bigger I'll have to take him back to pet store). I have 2 hob marineland 350's, a few bubble bars put together that span the entire length of the aquarium and a volcano that has it's own bubblemaker.

Anyway... I've always done weekly water changes because... well... I figured I was supposed to since it was overstocked and it'd keep my levels down. For the last month I've skipped a week and checked the levels at the end of the 2nd week. Today my ph is 6.6, phosphate .25 ppm, and nitrate between 0-5 ppm. 

So if after two weeks my levels are where they are I'm thinking about just start doing water changes every 2 weeks instead of every week. I usually do between 15-20gal change when I do. Why bother the fish putting a siphon in and pulling up all the "crud" in the water weekly. Is a phosphate level of .25 after 2 weeks to high for the fish to where i need to do a weekly water change as I was? Is there something else I'm missing as to why I would need to do weekly water changes?


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## susankat (Nov 15, 2008)

You should also be checking your ammonia and nitrite readings, If they are 0 then once every couple of weeks should be fine. But with a koi in the tank, they produce lots of waste and really do like different water parameters than your other fish. How about getting it a pond for outside. He would really be happy.


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## jrman83 (Jul 9, 2010)

Personally, I'd keep up with the weekly water changes. Sometimes that is personal pref though. You could keep the weekly but do a 10gal change instead of 15-20. I only pull 10gal a week from my 75gal tank. I haven't paid much attention to my levels. I know if I'm doing this amount, which only takes about 20min to do, my nitrate levels will take care of themselves.


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## archer772 (Nov 8, 2008)

There has been a big debate on another forum about this. I never tell people to do what I do so I wont go there. What do you have for filtration on your tank and what are you running in the filter. I would keep an eye on your levels and watch the fish but sounds like you could get away with WC's every 2-3 weeks.


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## Bulleyhead (Jul 16, 2010)

well i change my 10 gallon once a week, my 55 every 2 weeks, and my 30 a little less than twice every 3 weeks. The reason behind it is because the 10 gallon is filtered by 30 gallons of filtration, the 30 is filtered by 60 gallons of filtration but my 55 is only filtered by 75 gallons worth of filtration and i want to get another large filter for it...i try to stay double filtration for the size fo the tank...but in your case, i would just watch it and if there seems to be a rise in your results then i would do the change then...and base all changes after that, so if it take 3 weeks to make a difference in the numbers then do it every 2 1/2 weeks or so...thats just my thought but im not going to tell you how to do your fish tanks


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