Is high nitrate ok for established planted tank

[momsspaghett]

Hello. I have had this tank running around 3 years now and I have been able to grow and keep the beneficial bacteria's in my sponge and quartz rings. Today I checked my water after a couple months and read 0 ppm ammonia, ph 7.6, nitrite 0, nitrate 40 ppm. I have read a few reviews and comments of people with planted tanks keeping the nitrate levels around 20-40ppm and having no problems with it. They may have said it is pretty beneficial for the plants. Is there any opinions on this matter? Should I try to lower those levels or keep the tank running on its own and not mess with it. All of the inhabitants are doing well, I started with about 8-10 shrimp and have noticed at least 5-10+ added to the colony. It looks like they are thriving with the cories, apple snail I have in there as well. Any thoughts? Thanks.

 

[Essjay]

20 ppm nitrate is the highest fish should be kept in.

What is the nitrate level in your tap water? Most plants prefer ammonia as their nitrogen source and will only use nitrate if they've run out of ammonia. If you have enough fish to keep the plants fed, they won't remove any nitrate.
If your tap nitrate is high in nitrate you need to find some way of lowering it. But if your tap nitrate is low, the nitrate is getting into your tank some other way. With plants, it shouldn't be made from ammonia and the plants will remove that, which leaves plant fertiliser as a possibility - do you use a fertiliser, and if so what is it?

 

[outofwater]

In my humble opinion, if it ain't broke, don't fix it, unless you're planning on adding very sensitive fish

 

[Colin_T]

The plants are fine with high nitrate levels but fish and invertebrates (snails, shrimp, etc) won't do well long term in water with high nitrates.

As @Essjay said, 20ppm nitrate is the most you want in a tank that contains fish or inverts. Ideally you want 0ppm nitrates but that is hard to do so most people aim for less than 20ppm.

 

[momsspaghett]

20 ppm nitrate is the highest fish should be kept in.

What is the nitrate level in your tap water? Most plants prefer ammonia as their nitrogen source and will only use nitrate if they've run out of ammonia. If you have enough fish to keep the plants fed, they won't remove any nitrate.
If your tap nitrate is high in nitrate you need to find some way of lowering it. But if your tap nitrate is low, the nitrate is getting into your tank some other way. With plants, it shouldn't be made from ammonia and the plants will remove that, which leaves plant fertiliser as a possibility - do you use a fertiliser, and if so what is it?

So my ammonia and nitrite remains the same 0. The nitrate has been in the 40 ppm range and my fish in the tank haven’t died, the shrimp actually have grown more. I believe the spikes of the nitrate are when I use the fertilizer, which is flourish. I put in it there maybe every 3 weeks, so I wonder why the nitrate remains high. I added duckweed and salvia but I may have to get more to cover all of the surface. The plants remain green, a few leaves are yellow hence is why I add the fertilizer in small amounts (since it calls for little amounts). Other than that, I don’t understand why it remains so high, maybe it just needs more time to cycle? Any recommendations to what I could add to speed up the process?

 

[momsspaghett]

In my humble opinion, if it ain't broke, don't fix it, unless you're planning on adding very sensitive fish

Yes, that is also an opinion I hear about having high nitrates in planted tanks, so I don’t know what to listen to haha.

 

[Uberhoust]

There are a couple system at work. The plants will take some of the Ammonia and use it for the nitrogen they need, this bypasses the bacterial cycle. The rest of the ammonia would get taken up by the nitrogen cycle bacteria, which results in a continuous production of Nitrate that the plants don't like using. The result is the Nitrate builds up over time in the tank because there is no mechanism to remove it. The only way to prevent the buildup of nitrates is to have the plants process all of the generated ammonia in the tank, or more simply to remove the built up nitrate from time to time during the water changes.

Your situation is more complicated by the addition of fertilizers which may or may not contain nitrogen compounds used by plants, but also which affect the Nitrate levels.

In the past I am sure that people kept tanks with high Nitrate values >20 ppm, but as some people have already mentioned some fish start to show sensitivity to higher nitrate values. In general health affects due to Nitrate are slow to develop. At 40 ppm I would say your Nitrate is high but if your fish and shrimp seem OK then perhaps it is not an issue, it is likely you do not have very sensitive fish. I have some ornate tetras that seem to be sensitive to nitrates, they don't die or even behave that much differently but the closer to 20ppm Nitrate the more pale their coloration seems to me.

Really apples to oranges but I have been checking the Nitrates in stagnate bodies of water around my home and I haven't been able to find any traces of nitrate in natural water sources. The only place with any Nitrates had significant runoff from a dairy farm. Given it isn't common in natural environments suggests that maybe we should keep it low in the unnatural fish tank.

 

[itiwhetu]

For the sake of the fish, I aim for zero nitrates

 

[momsspaghett]

There are a couple system at work. The plants will take some of the Ammonia and use it for the nitrogen they need, this bypasses the bacterial cycle. The rest of the ammonia would get taken up by the nitrogen cycle bacteria, which results in a continuous production of Nitrate that the plants don't like using. The result is the Nitrate builds up over time in the tank because there is no mechanism to remove it. The only way to prevent the buildup of nitrates is to have the plants process all of the generated ammonia in the tank, or more simply to remove the built up nitrate from time to time during the water changes.

Your situation is more complicated by the addition of fertilizers which may or may not contain nitrogen compounds used by plants, but also which affect the Nitrate levels.

In the past I am sure that people kept tanks with high Nitrate values >20 ppm, but as some people have already mentioned some fish start to show sensitivity to higher nitrate values. In general health affects due to Nitrate are slow to develop. At 40 ppm I would say your Nitrate is high but if your fish and shrimp seem OK then perhaps it is not an issue, it is likely you do not have very sensitive fish. I have some ornate tetras that seem to be sensitive to nitrates, they don't die or even behave that much differently but the closer to 20ppm Nitrate the more pale their coloration seems to me.

Really apples to oranges but I have been checking the Nitrates in stagnate bodies of water around my home and I haven't been able to find any traces of nitrate in natural water sources. The only place with any Nitrates had significant runoff from a dairy farm. Given it isn't common in natural environments suggests that maybe we should keep it low in the unnatural fish tank.

Would you recommend just cleaning out substrate and water change of 25-50% to see if it decreases?

 

[momsspaghett]

For the sake of the fish, I aim for zero nitrates

How do you reach that level then?

 

[itiwhetu]

How do you reach that level then?

I have my tanks planted to over 50% of the volume of the tank, I use fast growing plants and keep trimming them.

 

[SomethingsFishy24]

How do you reach that level then?

If your nitrates are at 40ppm, a 50% water change will bring your Nitrates down to 20ppm, that is of course if you do not have Nitrates in the tap. If you have Nitrates straight out of the tap, that complicates things. A surface vaccum would not hurt. You can take a gradual approach, 25% change daily to get down to your target number so that temp or other parameters don't swing. Monitor from there to see how often and how much water needs replaced to maintain. Your plants will help in this, we want the plants growing and green but your fish to have water on the low end of nitrates. My planted tanks sit at 5-10ppm with ferts added as I have floating plants that sponge up the nutrients.

 

[Uberhoust]

Would you recommend just cleaning out substrate and water change of 25-50% to see if it decreases?

I see @SomethingsFishy24 has answered your question. I have a simple spreadsheet that you could use to roughly determine how often/how much to change your water to target a particular Nitrate concentration (Unfortunately it assumes the new water is at 0% nitrate).

 

[WhistlingBadger]

Just a slight aside. I have found, in thoroughly unscientific research, that java ferns start to do poorly in high nitrate water.

 

[momsspaghett]

If your nitrates are at 40ppm, a 50% water change will bring your Nitrates down to 20ppm, that is of course if you do not have Nitrates in the tap. If you have Nitrates straight out of the tap, that complicates things. A surface vaccum would not hurt. You can take a gradual approach, 25% change daily to get down to your target number so that temp or other parameters don't swing. Monitor from there to see how often and how much water needs replaced to maintain. Your plants will help in this, we want the plants growing and green but your fish to have water on the low end of nitrates. My planted tanks sit at 5-10ppm with ferts added as I have floating plants that sponge up the nutrients.

Alright thank you for that insight. I figured out that by tap, the ammonia is about .5 and the nitrate is 5.0. I have prime but of course that won’t clear up everything. Currently doing a 50% water change. About how long of 25% daily water changes would you suggest? Week, 2 weeks? Living in Utah, our water is high in minerals. My local fish store luckily has buffers they said I could use (beneficial minerals), anyone tried those before?