High nitrate levels won’t go down

Hello all,
I have been battling high nitrate levels for a long time and it just doesn’t seem to come down. My ammonia and ph is all fine just the nitrate is really high (160ppm). I have been to my local pet shop and asked them for advice and all they say is to do water changes. I do a water change every 6 days now to try and lower it and it doesn’t go down at all. I have tested my tap water and nitrate is 0ppm on there so I don’t understand why it won’t drop because today I woke up and there were 2 fish dead so I just don’t understand what to do anymore. If anyone knows how to actually lower it please let me know. Thanks.

 

Do a water change every day until it gets down to a good level

 

Do a water change every day until it gets down to a good level

How much percent a day should I do?

 

Unfortunately the answer is "waterchange".
Change 50% of the tank every day if you need to, until it's the same as your tap water

 

Unfortunately the answer is "waterchange".
Change 50% of the tank every day if you need to, until it's the same as your tap water

Ok I will give that a go, will it stress out my fish if I change the water everyday? And do I vacuum the gravel everyday also?

 

Unfortunately the answer is "waterchange".
Change 50% of the tank every day if you need to, until it's the same as your tap water then you test and every time it's at 40 ppm you waterchange to make it 20ppm, or if you set your limit at 20ppm nitrates, then every 50% will make it 10ppm. When it's buried in nitrates you can do water changes and see no change in the test, that's because it's higher than the test reading is saying.

The high nitrates are stressing your fish more than waterchanging will, it will improve conditions and relieve stress but they have adjusted over time to the high nitrates so the first changes can be rough on them, but not doing the water changes, they are going to continue to drop also.

The high nitrates are stressing your fish more than waterchanging will, it will improve conditions and relieve stress but they have adjusted over time to the high nitrates so the first changes can be rough on them, but not doing the water changes, they are going to continue to drop also.

Yes you should be vacuuming the gravel, however if you haven't done that in a while, you need to vacuum just 25% of the bottom at a time, until you've done the whole thing, then you can vacuum 100% at once after that. It's just being cautious because if it hasn't been done in a while and been undisturbed, a lot of nasty can be released to the water all at once.

 

Have you tested your tap water for Nitrate?

 

How are your fish!! Are they looking sick,stressed,hiding or just not right? Let’s see a pic of the test if you can. When changing water every 6 days how much are you changing? How big is your tank and how many and what types of fish? All this info helps.

 

If your nitrates are that high I would change 80% of your water do get it down. Water changes won't stress your fish. Just match the temp and refill slowly.

You also need to find out what's causing your high nitrates

 

If your nitrates are that high I would change 80% of your water do get it down.

It depends on how long its been high. If it had been awhile that big of change can stress them out too.

 

Yep if they’ve been high a long time an 80% change could kill them. But I think it’s just the api test kit and the guessing game!

 

Yep if they’ve been high a long time an 80% change could kill them. But I think it’s just the api test kit and the guessing game!

The test is hard to read at the high end. If you want a more accurate reading you dilute the sample 50/50 with clean water and double the results. If it it still dark red the level is over 300.

 

The test is hard to read at the high end. If you want a more accurate reading you dilute the sample 50/50 with clean water and double the results. If it it still dark red the level is over 300.

* distilled water. Still don't know if their tap has nitrate or not.

Also OP are you reading it at the 5 minute mark? It gets darker as it sits.

 

Hello all,
I have been battling high nitrate levels for a long time and it just doesn’t seem to come down. My ammonia and ph is all fine just the nitrate is really high (160ppm). I have been to my local pet shop and asked them for advice and all they say is to do water changes. I do a water change every 6 days now to try and lower it and it doesn’t go down at all. I have tested my tap water and nitrate is 0ppm on there so I don’t understand why it won’t drop because today I woke up and there were 2 fish dead so I just don’t understand what to do anymore. If anyone knows how to actually lower it please let me know.

A picture of the tank, and all of your water testing results are really needed to see how bad this problem really is and how to address it. At 160ppm nitrates, it's pretty much topped out for the test kit and it can be even much higher than that and not showing you in which case water changes won't change the test results until it gets back down into testable range.
Really need the test results for Ammonia, nitrite, nitrate, GH, KH, and pH to get the full picture of how bad it is.

I have a thread on here. I didn't do water changes, Just top offs, for 5 years. I had massive nitrates probably near 300ppm. At the time was only 6 fish in there.
thread is here:
High nitrates from water change neglect. What to do? | Aquarium Water Forum
Take a read, I had pH below 6 and 0 KH, meaning I had an acidity issue from all the nitrates also to contend with the more parameters are off the more dangerous it is to just "remove" nitrates, because water changes will bounce the other parameters too.


If it's ONLY a Nitrate run up, you have more room and less danger for the fish, but if all the parameters are off, PH down below 6, KH Zero, GH also high like the nitrates, you have to use care or risk osmotic shock of the fish.
Slow and steady small changes at first, get the waste out of the bottom in sections, clean up the filter so there's no "old waste" hanging around, and then start stepping up the water change percentage a bit more and a bit more.

I did this on the thread, it went from March, until November of 2022 before it started really sorting out and getting back in order.

No matter how bad the situation is though......
If you dont' want to spend that kind of time, and the money on water. I really suggest you remove the fish to a tub of the tank water, do 100% water change on the tank, vacuum the bottom, clean up everything in the tank and rinse the filter, and refill, and then drip acclimate the fish to the new improved conditions over 24 hours and hope they adjust that way. it's fast and it's effective to solve the problem with the least amount of water used, HOWEVER, there is some risk that the fish won't transition and go into shock. you will need aeration in the tub container at the minimum, the drip acclimation should slowly improve the bin conditions over time, you will need to remove some water here or there to make room for the drip water that gets added, and then top off the tank. Old water is cycled, new water is cycled by the tank filter, and it's letting the drip acclimation slowly replace all of the old tank water over time before the fish get added back to the tank.
It can be recovered in a weekend but no guarantee the fish will acclimate and not go into shock and die. there is risk doing it like this.
Just saying from experience, the slow water changes are safer and do work over time, but it's going to take hundreds to thousands of gallons of water and weeks/months to get it back in line depending on the severity of the situation.

 

* distilled water. Still don't know if their tap has nitrate or not.

Also OP are you reading it at the 5 minute mark? It gets darker as it sits.

The high nitrates are stressing your fish more than waterchanging will, it will improve conditions and relieve stress but they have adjusted over time to the high nitrates so the first changes can be rough on them, but not doing the water changes, they are going to continue to drop also.

Yes you should be vacuuming the gravel, however if you haven't done that in a while, you need to vacuum just 25% of the bottom at a time, until you've done the whole thing, then you can vacuum 100% at once after that. It's just being cautious because if it hasn't been done in a while and been undisturbed, a lot of nasty can be released to the water all at once.

* distilled water. Still don't know if their tap has nitrate or not.

Also OP are you reading it at the 5 minute mark? It gets darker as it sits.

I set a timer and read it at the 5 min mark. I’m gonna test everything and do a 50% change and I’ll let everyone know the results of the tests.
Thanks for the reply! I’ll take a picture of my tank and all the test results because I’m doing a 50% water change now and I’ll let everyone know how it all goes. Thanks!

A picture of the tank, and all of your water testing results are really needed to see how bad this problem really is and how to address it. At 160ppm nitrates, it's pretty much topped out for the test kit and it can be even much higher than that and not showing you in which case water changes won't change the test results until it gets back down into testable range.
Really need the test results for Ammonia, nitrite, nitrate, GH, KH, and pH to get the full picture of how bad it is.

I have a thread on here. I didn't do water changes, Just top offs, for 5 years. I had massive nitrates probably near 300ppm. At the time was only 6 fish in there.
thread is here:
High nitrates from water change neglect. What to do? | Aquarium Water Forum
Take a read, I had pH below 6 and 0 KH, meaning I had an acidity issue from all the nitrates also to contend with the more parameters are off the more dangerous it is to just "remove" nitrates, because water changes will bounce the other parameters too.


If it's ONLY a Nitrate run up, you have more room and less danger for the fish, but if all the parameters are off, PH down below 6, KH Zero, GH also high like the nitrates, you have to use care or risk osmotic shock of the fish.
Slow and steady small changes at first, get the waste out of the bottom in sections, clean up the filter so there's no "old waste" hanging around, and then start stepping up the water change percentage a bit more and a bit more.

I did this on the thread, it went from March, until November of 2022 before it started really sorting out and getting back in order.

No matter how bad the situation is though......
If you dont' want to spend that kind of time, and the money on water. I really suggest you remove the fish to a tub of the tank water, do 100% water change on the tank, vacuum the bottom, clean up everything in the tank and rinse the filter, and refill, and then drip acclimate the fish to the new improved conditions over 24 hours and hope they adjust that way. it's fast and it's effective to solve the problem with the least amount of water used, HOWEVER, there is some risk that the fish won't transition and go into shock. you will need aeration in the tub container at the minimum, the drip acclimation should slowly improve the bin conditions over time, you will need to remove some water here or there to make room for the drip water that gets added, and then top off the tank. Old water is cycled, new water is cycled by the tank filter, and it's letting the drip acclimation slowly replace all of the old tank water over time before the fish get added back to the tank.
It can be recovered in a weekend but no guarantee the fish will acclimate and not go into shock and die. there is risk doing it like this.
Just saying from experience, the slow water changes are safer and do work over time, but it's going to take hundreds to thousands of gallons of water and weeks/months to get it back in line depending on the severity of the situation.

Have you tested your tap water for Nitrate?

Yea I’ve tested my tap water and it is 0ppm so not sure how it got that high because I do a 20% water change every week.

 

How big of a tank and what’s in it?

 

Yea I’ve tested my tap water and it is 0ppm so not sure how it got that high because I do a 20% water change every week.

Nitrate adds up every week. When you change a small portion like 20% you really are not diluting it much at all. It will creep up little by little every week. So if it reads 40ppm and you change 20% it is only bringing it down to about 32ppm. If you did 50% it would be down to 20ppm. So you have roughly 10ppm adding up every week. (not doing exact math here just examples...lol)

Plus when you change small amounts of water the tank gets farther and farther parameters from your tap water. This can shock your fish every time you change water. Its my opinion that unless you have a full on Wahlsted tank you need to change water to dilute nitrates. Like 86 asked though what size tank does matter too. 20% may be sufficient in a 5g with a betta. Bio load is everything in WCs. Not a % someone said to do. You have to figure out how much your system needs weekly.

I change roughly 50% every week just so I dont have to worry about numbers and testing. My Nitrates may be getting a bit low right now because of light stock at the moment though.

 

How big of a tank and what’s in it?

It’s 36 litres and has guppy’s, baby guppies, a cory catfish and neons.

 

Ok guppies mass produce! That tank is maybe 10g. Being 10g/36l I’d change 5g/18l maybe twice a week. Being a small tank it’s that much harder to keep correct.

Next let’s see a picture of your nitrate test.

 

Just curious but how many adult fish are in the tank and roughly how many young guppies? What kind of filter are you using?

 

If your nitrate level is high and won't go down, I suspect the tank is either overstocked or overfed.

In an aquarium, the primary source of nitrogen is the protein in fish food. Those proteins are eaten by the live stock and converted to urea. That gets converted to ammonia, then to nitrite and then to nitrates. Thus, if the tank is overstocked or your are overfeeding the fish, you will be continually adding nitrogen and that will end up as nitrates.

Since you have a 10 gallon tank and you have guppies, your tank is likely to be overstocked. Guppies will generally continue to reproduce until the stocking limit is either reached or exceeded.

How often do you feed your fish? If you want to keep your guppies from multiplying, the best way to do that is to reduce feeding. If you want fish to breed, feed them multiple times per day and move fry to another tank. They conclude that life is good and it is a good time to bring fry into the world. If they are underfed, they do not grow as fast and they will not reproduce as fast. I had a 55 gallon tank that was overrun by platies. I keep the tank under control by feeding them once every three days. I just got back from an 8 day vacation and they were not fed at all while I was gone. They did just fine. Thus, consider reducing your feeding frequency and amount. Underfeeding is preferable to overfeeding.

Once nitrates are high, there are only two practical ways of reducing nitrates. One is to do frequent water changes. The other is to add live plants to the tank to consume nitrates as fertilizer. Some people add terrestrial plants to their tank like pothos vine. The leaves of the plant are left above water with only the roots are submerged. If the room is well lit, the pothos will grow well and remove nitrates from the water. Sweet potato vines are also good for this purpose. However, before attempting to use an emerged plant, be sure to read up on the proper way of doing this. In order to grow efficiently, you might need to add other nutrients like potassium and phosphorus as the nitrates only supply needed nitrogen.

 

Unfortunately the answer is "waterchange".
Change 50% of the tank every day if you need to, until it's the same as your tap water

You just want to do water changes until your nitrate level gets to be 20ppm or lower. Then going forward you want to do enough water changes to keep your nitrate level under 40ppm.

 

Hi, asking if Prime will help protect the fish during this process?

 

Hi, asking if Prime will help protect the fish during this process?

I honestly don’t know but I tend to doubt it. In any case, 50ppm of nitrate, though it is high, is not crazy high. I’ve seen tanks where it was over 150ppm. So I’d just do the water changes that are necessary to keep it as low as you want it.

 

I honestly don’t know but I tend to doubt it. In any case, 50ppm of nitrate, though it is high, is not crazy high. I’ve seen tanks where it was over 150ppm. So I’d just do the water changes that are necessary to keep it as low as you want it.

This is so true. We’ve read so many times of people who never checked nitrates and when they did found them to be very high 150-200ppm. If they never checked they’d have never known. Their fish were fine and they weren’t adding new fish. These people all had one thing in common. They never changed water and only added for evaporation. Fish have adjusted to the nitrates. It would be deadly to change 50% or higher water to these fish. The change would kill them. It would also be deadly to add new fish. The high nitrate would kill new fish (many found out about high nitrates this way). To fix this you need to do daily 15% water changes or twice daily. May take a month or 2 to bring it back to normal.
this whole “you need low nitrates” has a lot to do with sales of media’s. Especially the ones claiming to reduce nitrates . Funny thing is none of these media’s work better than sponge! Not fiction. Fact!!

 

When you nitrate test shows 160 ppm on the color chart, it is common to think that the nitrate concentration is 160 ppm. Howver, even if the nitrate concentration is 160,000 pm, it will still show the same test result.

If the concentration is 160 ppm, you should be able to do a 50% water change and reduce the nitrates to 80 ppm, a second 50% change will reduce the nitrates to approximately 40 ppm and a third water change will reduce them to 20 ppm, which is where you want to be.

If you do a 50% water change and the test still shows 160 ppm, that means the nitrates are 320 ppm or even higher. Depending on the exact concentration, it might take several 50% water changes before you even start to see a noticeable difference in the nitrate test results.

If you want to know how high your nitrates really are, you can always use a method called serial dilution.
Measure a 5 ml sample of aquarium water as you normally would, but rather than testing it, dilute the sample to a total volume of 50 ml using distilled water. Mix well and then take a 5 ml sample as you normally would and run the nitrate test. Once you get the test result, multiply it by 10. If your dilution test shows 40 ppm, multiply it by 10 to get a real concentration of 400 ppm.

 

Hi, just came across this thread. How is the Nitrate issue going? Just curious about your filter. I’ve heard that soiled filter media could be an issue with Nitrates as well. Just wondered if you have done a filter media rinsing?
Hope you are getting better numbers.
Cheers!
Eric