Nitrates refuse to go down?

[Fiji]

Hello everyone. I have been battling a dilemma with my 55 gallon tank for some time now and figured it was time to ask for advice. For the past 3-4 months every time I measure the nitrates level it reads 40-80 ppm which is obviously not good. The tank is not heavily stocked and I've been doing monthly/bi-monthly 50% water changes with hope that the nitrates will come down; unfortunately they do not. In fact, the nitrate level does not ever change. I'm hoping to add some new fish soon but I don't think that'd be a good idea until I get everything as close to zero as possible. Looking for anything that would help me out. Thanks
Last water change (6/18/17):
Nitrates- 80 ppm
Nitrites- 0 ppm
Ammonia- .25 ppm
pH- 8.2

 

[StevenF]

First question is what is the nitrate level in your tap water? If you tap water has high nitrates you may need to filter your tap water or use distilled or RO water before adding it to the tank. Most people do one water change per week. If your nitrates were good one water change every other week is Ok. But since your levels are high once a week or more often would be better.

 

[Fiji]

First question is what is the nitrate level in your tap water? If you tap water has high nitrates you may need to filter your tap water or use distilled or RO water before adding it to the tank. Most people do one water change per week. If your nitrates were good one water change every other week is Ok. But since your levels are high once a week or more often would be better.

Tap water nitrates read 0 ppm.

 

[NickAu]

The tank is not heavily stocked and I've been doing monthly/bi-monthly 50% water changes

Tap water nitrates read 0 ppm.

Try changing 50% of the water once a week. Monthly/Bi-Monthly is not enough.

 

[Fiji]

Try changing 50% of the water once a week. Monthly/Bi-Monthly is not enough.

One of my buddies in the hobby suggested doing 30% water changes daily until I see a drop in the nitrate level. Is this a good plan for the moment?

 

[NickAu]

One of my buddies in the hobby suggested doing 30% water changes daily until I see a drop in the nitrate level. Is this a good plan for the moment?

Yes that should work. Never be afraid to do water changes there is no such thing as too much clean water, What type of water conditioner do you use?

 

[Byron]

Having pinned down the nitrates to within the aquarium (the spurce water being zero), this can occur from one or more of the following: insufficient water changes, which involves both volume of each and the frequency; too many fish, which can mean too many in numbers or too large sized for the tank; insufficient cleaning of the substrate (organics build here, which is good and wanted, and plants will benefit, but it has to be controlled); insufficient filter cleaning (organics, the brown gunk, accumulates and can add nitrates plus impede water flow); inadequate filtration (this is a bit of a red herring, as the afore-mentioned issues such as the fish load and water changes can make filters unnecessary, but it is still a factor); too much plant fertilizer; and specialized substrates (soil for example can be bad for ammonia and nitrate).

As nitrates are above 40 ppm you definitely need to look at the above factors and see if any apply. Nick has mentioned increased frequency of water changes, and this is absolutely the single most important factor in any aquarium. Every week should be minimum, with the volume depending but I aim for 50-65% of the tank volume once a week. More frequent and more volume changes will work to maintain more stable water conditions in any aquarium, problems or not. Nothing else is as important as WC's.

Nitrates should be as low as possible, and never above 20 ppm using our basic aquarium kits like the API. Nitrate, like ammonia and nitrite, is poisonous to all fish; with nitrate, it is a matter of the level and the exposure, and the effects vary among fish species. Young fish and fry are most vulnerable too. This should not be surprising, when we consider than none of the natural habitat waters where our fish come from have nitrates above 1 ppm, and many are zero. My tanks run in the zero to 5 ppm range, and have for literally decades. I would probably have zero if I had fewer fish, but the tanks are certainly not over-crowded, just nicely filled with appropriate numbers of species and my live plants plus water changes keep nitrates well in check. By the way, waiting until you see nitrates rise before doing water changes, as some still advise, is waiting too late. The damage of nitrates is already occurring. While this is still an area largely undocumented, the reliable sources in the hobby will agree that nitrates seem to weaken fish physiologically, which of course means other issues are more likely to occur, and almost always a shorter than normal lifespan.

Byron.

 

[Fiji]

Yes that should work. Never be afraid to do water changes there is no such thing as too much clean water, What type of water conditioner do you use?

Seachem Prime

 

[Fiji]

Having pinned down the nitrates to within the aquarium (the spurce water being zero), this can occur from one or more of the following: insufficient water changes, which involves both volume of each and the frequency; too many fish, which can mean too many in numbers or too large sized for the tank; insufficient cleaning of the substrate (organics build here, which is good and wanted, and plants will benefit, but it has to be controlled); insufficient filter cleaning (organics, the brown gunk, accumulates and can add nitrates plus impede water flow); inadequate filtration (this is a bit of a red herring, as the afore-mentioned issues such as the fish load and water changes can make filters unnecessary, but it is still a factor); too much plant fertilizer; and specialized substrates (soil for example can be bad for ammonia and nitrate).

As nitrates are above 40 ppm you definitely need to look at the above factors and see if any apply. Nick has mentioned increased frequency of water changes, and this is absolutely the single most important factor in any aquarium. Every week should be minimum, with the volume depending but I aim for 50-65% of the tank volume once a week. More frequent and more volume changes will work to maintain more stable water conditions in any aquarium, problems or not. Nothing else is as important as WC's.

Nitrates should be as low as possible, and never above 20 ppm using our basic aquarium kits like the API. Nitrate, like ammonia and nitrite, is poisonous to all fish; with nitrate, it is a matter of the level and the exposure, and the effects vary among fish species. Young fish and fry are most vulnerable too. This should not be surprising, when we consider than none of the natural habitat waters where our fish come from have nitrates above 1 ppm, and many are zero. My tanks run in the zero to 5 ppm range, and have for literally decades. I would probably have zero if I had fewer fish, but the tanks are certainly not over-crowded, just nicely filled with appropriate numbers of species and my live plants plus water changes keep nitrates well in check. By the way, waiting until you see nitrates rise before doing water changes, as some still advise, is waiting too late. The damage of nitrates is already occurring. While this is still an area largely undocumented, the reliable sources in the hobby will agree that nitrates seem to weaken fish physiologically, which of course means other issues are more likely to occur, and almost always a shorter than normal lifespan.

Byron.

Back when I did monthly water changes (last one was yesterday) I made sure to thoroughly vacuum as much debris from the gravel as possible so I'm a little confused how that could still be a major contributor. How exactly am I supposed to clean the filter? I was under the impression that the filter was a haven for helpful bacteria? Thanks

 

[Byron]

Back when I did monthly water changes (last one was yesterday) I made sure to thoroughly vacuum as much debris from the gravel as possible so I'm a little confused how that could still be a major contributor. How exactly am I supposed to clean the filter? I was under the impression that the filter was a haven for helpful bacteria? Thanks

I listed the various factors that can cause nitrates, not suggesting all apply. But obviously one or more must, or you wouldn't have nitrates above 40 ppm. So your nitrates now may not be due to the substrate necessarily.

Bacteria in a freshwater aquarium are many and varied in function. Most aquarists think of the nitrifiers when they see "bacteria," and these are primarily in the filter but also in the substrate. The nitrifiers use ammonia to produce nitrite ( these are the Nitrosomonas sp. bacteria) and then nitrite to produce nitrate (Nitrospira sp.). There are then denitrifying bacteria that can use nitrate to change it back into nitrogen gas which enters the atmosphere.

Waste control bacteria are species of heterotrophic bacteria that break down dead organic matter like fish waste, dead fish or plant matter, uneaten fish food, dead bacteria, etc. Some are aerobic, but many species are facultative anaerobes, able to live with or without oxygen. Like all bacteria, they colonize surfaces, and these are most prevalent in the substrate and the filter media. Many species can survive complete drying, allowing them to remain potent even when filter media that has been previously used is completely dry. These bacteria have only one requirement to appear and live: organics. They compete with autotrophic bacteria for both oxygen and surface area; studies show that even in relatively clean environments, they occupy more than 50% of the available surface area. And given that they can reproduce within 15-60 minutes—compare this to the 12-32 hours required by nitrifying bacteria—you can see how easily these heterotrophic bacteria can overwhelm the system. In a filter, if sludge is allowed to increase, heterotrophic bacteria will multiply so fast they actually smother and kill the autotrophic nitrifying bacteria. Keeping the filter clean of organics (that brown sludge) is crucial to control this. Rinsing the filter media under the tap will not kill off all these bacteria as some think, though in new tanks using a bucket of tank water is OK.

Live plants usually mean lower nitrates, all else being equal, because the plants quickly take up ammonia and therefore less is used by bacteria so nitrite and thus nitrate are less. Plants also can take up some nitrate, especially the fast growers.

Seachem Prime was mentioned, and this conditioner detoxifies ammonia, nitrite and nitrate. However, this can be misleading, because the detoxification only lasts 24-48 hours, after which if it is still present, the ammonia or nitrite or nitrate reverts back to the toxic form. Prime should not be thought of as some sort of treatment for ammonia/nitrite/nitrate, but only as a temporary remover of whichever if they occur in the source water (which they don't here). Prime's detoxification of these allows the bacteria to take over after the initial influx of them with water changes. As I said, this is not what you have, but I just point it out. Nitrate occurring within the aquarium has to be dealt with by eliminating the source until you get the nitrate down to an acceptable level and it remains there from water change to water change. High levels of nitrate, above 40 ppm, have been shown to slow fish growth, suppress breeding, and depress the immune system making the fish much more susceptible to disease. While different fish species show some variation in tolerance, a level below 20 ppm is recommended, and preferably below 10 ppm.

Byron.

 

[Crystal90]

My regular schedule is 50% water changes every week on my 40g. I do a cleaning every other week. My eheim canister filter is cleaned every 2-3 months. I definitely agree with more water changes. A water change only takes 20 minutes or so, it shouldn't be a problem to incorporate this into your schedule.