Very high nitrates - The Planted Tank Forum
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post #1 of 4 (permalink) Old 02-17-2016, 06:55 AM Thread Starter
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Very high nitrates

I have a ten gallon with very high nitrates. When using a test kit the nitrates color is about the color of red wine. Fish and shrimp don't seem too stressed or dying. I've done three 50 percent water changes every other day and it's still very high.

If I do a 80 percent water change, will it have any ill effects on my fish or send my tank through another major cycle?

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post #2 of 4 (permalink) Old 02-17-2016, 07:17 AM
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Reduce feeding's and 50% weekly water change .
See that no one else is feeding the tank.
Get second opinion or test result's for nitrates.
Reduce KNO3 from fertilizer routine if adding it.?
Keep filter clean.
Add more plant's.
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post #3 of 4 (permalink) Old 02-17-2016, 07:30 AM
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First I would start with finding the source of those high nitrates. If there are very high nitrates in your tap water, 80% water change is not going to help you. If the source is overfeeding, overdosing ferts (liquid or root tabs) or maybe a dead fish stuck somewhere or decomposing plants as a source of ammonia, you have to clean that up first. And continue with 50% water changes every other day until it gets to acceptable levels. Do you have any NH3/NH4 and NO2 tests? If you can detect any ammonia or nitrites, that may be your source of high NO3, considering you have good bio filtartion.
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post #4 of 4 (permalink) Old 02-17-2016, 09:15 AM
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First calibrate your test kit to make sure it's reading correctly.

Check your tap water.

If you are dosing KNO3 fertilizer, then stop.

If the high nitrate readings are correct, try eliminating/great reducing elements (feeding, etc.) that add to the nitrogen load (anything that will convert down to nitrates, making more)

Inhabitants can actually tolerate very high levels of Nitrates for quite a long time (several months, of course levels within reason and depending on species).

Since you are not seeing any signs of stress, I wouldn't rush things. Many people say large water changes can be harmful to shrimp, so the large (80%) water change will most likely be a lot more harmful than staying in high nitrates levels waiting for you to do smaller water changes.

Large water changes in itself aren't really harmful to beneficial bacteria, unless you have significant temperature, pH, etc, differences. So if all other water parameters are pretty much the same, a large water change wouldn't be a problem really. Do make sure you use enough dechlorinator/water conditioner though. Fish do appreciate smaller water changes over large water changes, pretty much for the same reason. Even if fish seem to really appreciate large water changes even if the parameters are pretty different, the adjustments their body is doing to readjust/readapt to the water parameters does put a bit more of a toll on fish's insides (shrimp and certain fish being more sensitive than others). Although not really noticeable unless a really drastic change.
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