Nitrate levels

Byron said:

Welcome to TFF.

Nitrate along with ammonia and nitrite are the three forms of nitrogen we encounter in an aquarium; there is also nitrogen gas, but that is another issue. While ammonia and nitrite are very highly toxic in low levels and quite rapidly, nitrate is different. The level of nitrate (here you mention 20 ppm), the period of time the fish are exposed, and the individual species all factor in to how nitrate harms the fish.

Generally speaking, the nitrate should be as low as we can keep it, and never above 20 ppm. We now know that even at 20 ppm, many fish will slowly weaken; cichlids are particularly sensitive, and there are others. And some species will experience this at much lower levels if they are continuously exposed.

Nitrate occurring within the aquarium is more easily dealt with, than nitrate that might be present in the source (tap) water to begin with. If you have not already done so, test the tap water on its own for nitrate.

When I have your response to the above, I'll be better able to suggest how to deal with this. The source water nitrate level (if any), the fish species in the tank, and if live plants are present.

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Angelmarina said:

Thank you for the welcome. The tank is cycled no ammonia or nitrites it’s been set up a few months. I have both female and male guppies at the moment. There are live plants in the tank.

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Angelmarina said:

Yes these are the nitrate levels in my water supply. Thanks

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Byron said:

Which number, 1.38 or 50? But that brings up the issue of the "nitrate" which I can't remember for the moment, as there are two measurements and they are substantially different. If you have a nitrate test, can you just test the tap water? This being an aquarium test will have the unit we want.

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Byron said:

OK, then most of the 20 ppm is occurring within the tank. As you likely know, ammonia is changed to nitrite, then nitrite to nitrate. Ammonia, and nitrate itself, are produced from organics, so reducing organics is the key to reducing/removing nitrate as much as possible. The fish load and how much they are fed are the first thing to look at, followed by water changes (a larger volume change removes more dissolved organics), keeping the filter well rinsed, and vacuuming the substrate in open areas. Live plants also help, not so much by taking up nitrate as by grabbing ammonia and unlike the bacteria this does not result in nitrite or nitrate.

So I would consider these factors, esp not overfeeding (once a day, even skipping a day or two each week is more than enough except for fry), partial water changes once each week with 50-70% of the tank volume changed at each, keep the filter rinsed (I do mine at each water change), and have floating plants as these are real ammonia sponges (which means less nitrate down the road). If the tap water is close to zero, you should not see nitrate above 10 ppm and possibly closer to 5 ppm. This will absolutely mean better lives for the fish than 20 ppm.

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