# Hi Nitrates and fish health?



## zyglet1 (Jul 1, 2009)

Someone told me not to worry if my nitrate levels were high. He said that ammonia and nitrite kill fish quickly and that nitrates have a long term effect on fish but that it would not kill the fish quickly. I try to keep all of my water chemistry levels in order but on occasion my nitrates creep up. Has anyone experienced this yet? 

How important is it to monitor GH and KH in fresh water tanks?


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## jeaninel (Aug 24, 2007)

I try to keep my nitrates as low as possible through weekly water changes. My levels are usually around 5-10ppm by water change day. Yes, high levels of nitrates do have a long term effect on the fish. It won't kill the fish quickly but they will not be as healthy and are more prone to disease and sickness. It's like a person living in a very polluted area of the country where there are higher incidents of cancer and lung problems. 

Kh and Gh...I think once your tank is cycled and stabilized you really don't have to continually check these. It's nice to know what they are but they don't really change. At least mine have always been the same reading. Don't know if anyone else has ever experienced flucuations iin Kh and Gh.


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## willow (Sep 9, 2006)

i try and keep the nitrates down too,and the water changes take care of that.


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## 1077 (Apr 16, 2008)

I too try and keep NitrAtes low with water changes. Some fish can tolerate nitrate levels better than others but ALL fish will in my view, remain healthier with low NitrAte levels.Cichlids and corydoras seem especially sensitive to nitrAtes much above twenty. IMHO


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## Byron (Mar 7, 2009)

Concur with previous posts. Curious as to what you actually mean by "high" nitrates? Some people might consider 20ppm as "high" but it is not. As was mentioned, the weekly partial water change removes/dilutes nitrates and unless something is biologically wrong in the aquarium this will suffice. Plants also consume nitrates, and anaerobic bacteria in the substrate, but it is the pwc that most keeps them in balance. Anything below 40ppm is considered to be basically safe, but as 1077 pointed out some fish do better with lower nitrates than this, and most authors recommend keeping them below 20ppm which will occur with weekly pwc. I have heavily stocked aquaria and they are fairly heavily planted, and the nitrates are constant at 5-10ppm, and I do a 40-50% pwc every week.

Hardness depends upon your tap water and any substances in the tank that might raise or lower it (calcium-base rocks and gravel raise it, peat filtration lowers it). Like pH, the hardness tends to lower very slightly over time due to the normal biological processes, and here again the weekly pwc keeps it in balance.


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