my ten gallon tanks keep showing 5-10 mg nitrate despite 50% water changes about every 10 days, however , shortly after changing water last week the level was still above 5, how can this be?
nitrate problems
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, Feb 12 2014 07:57 PM
23 replies to this topic
#3
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Posted 13 February 2014 - 05:52 AM
Ever check the nitrates on your tapwater?my ten gallon tanks keep showing 5-10 mg nitrate despite 50% water changes about every 10 days, however , shortly after changing water last week the level was still above 5, how can this be?
#4
Guest_Erica Lyons_*
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Posted 13 February 2014 - 09:36 AM
No, really, it sounds normal even if their tap water is 0 ppm nitrate (as it should be). If you do a 50% water change with the nitrate at 10 ppm, it dilutes it by half and leaves it at 5. That's how dilution math works; you halve the concentration. I doesn't drop to 0 unless you do a 100% water change, which depending on your kH, DH, and pH, will usually shock the fish.
By the way, 5 is really low. You can easily get that much just from the degradation of mulm in between the gravel rocks in a well cycled, aged tank. The only time my 10 gallon tank had 0 ppm nitrate was when I got a population of in-tank blackworms to feed the fish, stopped feeding fish flakes, and had a live plant. The live plant (ceratophyllum) promptly died from lack of food. 0 ppm nitrate is really dangerous for rootless plants. 5 is like the minimum. Most test kits won't read below that, and you want a readable number so your plants don't starve and you know your nitrifying bacteria are still active.
Here, I got an article for you.
http://www.ncbi.nlm....pubmed/17932709
"Abstract
Juvenile bay scallops (7.2-26.4 mm) were exposed for 72 h to different concentrations of un-ionized ammonia, nitrite, or nitrate. Using the Trimmed Spearman Karber method, 50% lethal concentrations (LC(50)) and 95% confidence limits were calculated individually for each. Un-ionized ammonia concentrations above 1.0 mg N-NH(3)/L resulted in 100% scallop mortality within 72 h. The 72-h LC(50) for un-ionized ammonia was calculated at 0.43 mg N/L. At nitrite concentrations of 800 mg N/L or higher 100% mortality was observed. The 72-h LC(50) for nitrite was calculated at 345 mg N/L. Nitrate was the least toxic, with 100% mortality observed at a concentration of 5000 mg N/L. The calculated nitrate 72-h LC(50) was 4453 mg N/L. Our results indicate that un-ionized ammonia is the most lethal nitrogenous waste component to bay scallops."
See, nitrate at 5 ppm is fine. (ppm = mg/L). It's the ammonia and nitrite you don't want, and the way to not have ammonia or nitrite is to use bacteria to convert them into nitrate. 5 ppm ammonia would flat out kill your fish. 5 ppm nitrate is very comfortable for them. It's the same number of nitrogen atoms, just surrounded by oxygen instead of hydrogen, and 10,000 times less toxic. In general, I don't worry about nitrate unless it's above 30 ppm. Discus and cichlids are a bit more sensitive, but I've got live plants in my Lake Victoria tank, so nitrogen's not a problem. The plants suck it out of the water so fast, it's hard to make it hit 30 ppm unless I dump like a pound of food in that tank.
My point? 5 ppm after a 50% water change with the original concentration around 10 ppm sounds totally normal and healthy for the fish.
By the way, 5 is really low. You can easily get that much just from the degradation of mulm in between the gravel rocks in a well cycled, aged tank. The only time my 10 gallon tank had 0 ppm nitrate was when I got a population of in-tank blackworms to feed the fish, stopped feeding fish flakes, and had a live plant. The live plant (ceratophyllum) promptly died from lack of food. 0 ppm nitrate is really dangerous for rootless plants. 5 is like the minimum. Most test kits won't read below that, and you want a readable number so your plants don't starve and you know your nitrifying bacteria are still active.
Here, I got an article for you.
http://www.ncbi.nlm....pubmed/17932709
"Abstract
Juvenile bay scallops (7.2-26.4 mm) were exposed for 72 h to different concentrations of un-ionized ammonia, nitrite, or nitrate. Using the Trimmed Spearman Karber method, 50% lethal concentrations (LC(50)) and 95% confidence limits were calculated individually for each. Un-ionized ammonia concentrations above 1.0 mg N-NH(3)/L resulted in 100% scallop mortality within 72 h. The 72-h LC(50) for un-ionized ammonia was calculated at 0.43 mg N/L. At nitrite concentrations of 800 mg N/L or higher 100% mortality was observed. The 72-h LC(50) for nitrite was calculated at 345 mg N/L. Nitrate was the least toxic, with 100% mortality observed at a concentration of 5000 mg N/L. The calculated nitrate 72-h LC(50) was 4453 mg N/L. Our results indicate that un-ionized ammonia is the most lethal nitrogenous waste component to bay scallops."
See, nitrate at 5 ppm is fine. (ppm = mg/L). It's the ammonia and nitrite you don't want, and the way to not have ammonia or nitrite is to use bacteria to convert them into nitrate. 5 ppm ammonia would flat out kill your fish. 5 ppm nitrate is very comfortable for them. It's the same number of nitrogen atoms, just surrounded by oxygen instead of hydrogen, and 10,000 times less toxic. In general, I don't worry about nitrate unless it's above 30 ppm. Discus and cichlids are a bit more sensitive, but I've got live plants in my Lake Victoria tank, so nitrogen's not a problem. The plants suck it out of the water so fast, it's hard to make it hit 30 ppm unless I dump like a pound of food in that tank.
My point? 5 ppm after a 50% water change with the original concentration around 10 ppm sounds totally normal and healthy for the fish.
#5
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Posted 13 February 2014 - 09:45 AM
And Ferraris should fall gently from the skies into my driveway! I can't count the number of times I've heard of folks complaining that they couldn't get their nitrates down to 0 in their reef tanks no matter how much water they changed, then finding out that they used our Philadelphia tapwater drawn from surface sources which routinely contains 2-4 ppm nitrate. The township out in the beautiful farmland (well it was 30 years ago!) where my mother lives has its own wells. Around 20 years ago I tested her tapwater and got readings approaching 60 ppm, far in excess of the federal guidelines of 20 ppm. She has a whole house RO now.......No, really, it sounds normal even if their tap water is 0 ppm nitrate (as it should be). If you do a 50% water change with the nitrate at 10 ppm, it dilutes it by half and leaves it at 5. That's how dilution math works; you halve the concentration. I doesn't drop to 0 unless you do a 100% water change, which depending on your kH, DH, and pH, will usually shock the fish.
By the way, 5 is really low. You can easily get that much just from the degradation of mulm in between the gravel rocks in a well cycled, aged tank. The only time my 10 gallon tank had 0 ppm nitrate was when I got a population of in-tank blackworms to feed the fish, stopped feeding fish flakes, and had a live plant. The live plant (ceratophyllum) promptly died from lack of food. 0 ppm nitrate is really dangerous for rootless plants. 5 is like the minimum. Most test kits won't read below that, and you want a readable number so your plants don't starve and you know your nitrifying bacteria are still active.
#6
Guest_Erica Lyons_*
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Posted 13 February 2014 - 09:56 AM
I can't comment on the well water thing because I don't know anything about drinking water.
My solution to the saltwater person who wanted 0 ppm nitrate when their tap water could range up to 6 ppm would have been to add things that eat nitrates.
Read Table 2 here: http://www.theaquari...ical_Filtration
Plants will eat nitrate. Water lettuce would eat 6 ppm nitrate in less than two days.
There are saltwater 'plants'. This was my native saltwater tank. I live in North Carolina at the moment, where if you snorkel off shore you can find caulpera prolifera and hippocampus zosterae.
http://www.youtube.com/watch?v=ppOte9qOb9M
Caulerpa prolifera eats nitrate.
I talk to a lot of saltwater people about this. Usually the thing that sways them over to my side (that macroalgaes are good, since they eat nitrate, and are worth having) is purple ochtode.
http://www.ebay.com/...=item2eceae68f6
Macroalgae comes in basically all colors. Red, yellow, green, blue, purple, brown, etc. Here's a page with lots of pictures. http://live-plants.com/
Don212, if you want 0 ppm nitrate, either add a rooted plant or increase the frequency of your water changes. There's only two ways for nitrate to get out of a freshwater aquarium: water changes and plant trimming. But like I posted above with the LC50 study, nitrate's LC50 was like, 5000 mg/L. Five is fine. Please don't do any more than a 50% water change (even that's a lot) because large percentage water changes can shock fish. Temperature, KH, GH, pH, salinity, basically any difference between tap and tank water can kill sensitive fish. It sounds like you're feeding really lightly if you're doing a water change every 10 days and only have 5 ppm nitrate. Your tank sounds fine. Very healthy and normal.
My solution to the saltwater person who wanted 0 ppm nitrate when their tap water could range up to 6 ppm would have been to add things that eat nitrates.
Read Table 2 here: http://www.theaquari...ical_Filtration
Plants will eat nitrate. Water lettuce would eat 6 ppm nitrate in less than two days.
There are saltwater 'plants'. This was my native saltwater tank. I live in North Carolina at the moment, where if you snorkel off shore you can find caulpera prolifera and hippocampus zosterae.
http://www.youtube.com/watch?v=ppOte9qOb9M
Caulerpa prolifera eats nitrate.
I talk to a lot of saltwater people about this. Usually the thing that sways them over to my side (that macroalgaes are good, since they eat nitrate, and are worth having) is purple ochtode.
http://www.ebay.com/...=item2eceae68f6
Macroalgae comes in basically all colors. Red, yellow, green, blue, purple, brown, etc. Here's a page with lots of pictures. http://live-plants.com/
Don212, if you want 0 ppm nitrate, either add a rooted plant or increase the frequency of your water changes. There's only two ways for nitrate to get out of a freshwater aquarium: water changes and plant trimming. But like I posted above with the LC50 study, nitrate's LC50 was like, 5000 mg/L. Five is fine. Please don't do any more than a 50% water change (even that's a lot) because large percentage water changes can shock fish. Temperature, KH, GH, pH, salinity, basically any difference between tap and tank water can kill sensitive fish. It sounds like you're feeding really lightly if you're doing a water change every 10 days and only have 5 ppm nitrate. Your tank sounds fine. Very healthy and normal.
#7
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Posted 13 February 2014 - 01:06 PM
My point is that almost all tapwater contains nitrates. You should get an assay from your water company. If the op's tapwater contains 5 ppm nitrate, which isn't unlikely, all the changes in the world won't get it any lower.
#8
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Posted 16 February 2014 - 09:04 AM
thank you all for your comments, i'll have to look for other reasons for fish mortality, I have never gotten near 30 ppm, my kit is over a year old, my tap water tests 0 with this kit, my aquariums are heavily planted but could use some trimming, my tapwater is city water with a whole house sediment , carbon and magnetic filter, maybe i'll have it tested professionally.
#12
Guest_Erica Lyons_*
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Posted 18 February 2014 - 12:49 AM
It's a toxicity bioassay method. It's described here: http://www.math.mont...armanKarber.pdfWhat is that? - I'm not familiar with it.
The result is you find out what concentration of a thing kills half the population. That's the LC50, the lethal concentration that kills 50%.
#13
Guest_Irate Mormon_*
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Posted 18 February 2014 - 10:05 PM
I know what LC 50 is of course, but I have never heard of that particular method. Of course, I don't do toxicity studies any more either, other than the one time I tested various substances on leftover fishing minnows (hey, I was in high school or something). Surprising fact: Fathead minnows can live a LONG time in Suave shampoo (strawberry scented).
#14
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Posted 19 February 2014 - 06:08 AM
But a 6" length of garden hose in a gallon of water wipes the slate of Fatheads!I know what LC 50 is of course, but I have never heard of that particular method. Of course, I don't do toxicity studies any more either, other than the one time I tested various substances on leftover fishing minnows (hey, I was in high school or something). Surprising fact: Fathead minnows can live a LONG time in Suave shampoo (strawberry scented).
#16
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Posted 20 February 2014 - 06:15 AM
We were setting up an aquatic bioassay program at a private testing lab, a soup to nuts operation where we produced our own test organisms in house. We went through the whole operation with a fine toothed comb looking for any potential interference with the results. As I topping off the Fathead system after a cleaning, I looked down at the garden hose I was refilling the sump with and thought "hmmmm!" So I took a bucket and threw in 10 fry, and then cut a section off the end of the hose and put it in. Seemed fine when we left, but next morning there were 10 dead fry. So we repeated the trial with exactly the same results. We went to the local RV place and bought hose rated for potable water, repeated the test and survival was 100% for a couple days. I always get a kick out of folks telling me that rubber garden hoses are fine to use for refilling tanks.
#17
Michael Wolfe
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Posted 20 February 2014 - 08:02 AM
Kind of a threadjack at this point, but that is a very interesting data point. I wonder if this is like an a coating or something that was supposed to keep fungus from growing in or on the hose? I remember some folks talking about rubber sheeting used for roofs. Excess materials would make for good pond liners, but some of it has a pretty aggressive anti fungal coating. Did you ever follow up on that, or just move on to the potable water hose?
Either write something worth reading or do something worth writing. - Benjamin Franklin
#19
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Posted 20 February 2014 - 09:31 AM
I use RV drinking-water rated hoses in my fish room, and I'm pretty sure the inspiration to do that came from reading something that said that most garden hoses are chemically imbued with anti-fungus and/or anti-mildew agents. Distant past however, I don't have a reference handy.I wonder if this is like an a coating or something that was supposed to keep fungus from growing in or on the hose? I remember some folks talking about rubber sheeting used for roofs. Excess materials would make for good pond liners, but some of it has a pretty aggressive anti fungal coating. Did you ever follow up on that, or just move on to the potable water hose?
#20
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Posted 14 June 2014 - 12:16 PM
Sorry for resurecting an old thread. I've been catching up after a long absence from the forum.
1. Nitrate does not kill fish in levels found in aquariums.
2. Many private wells and public water supplies have elevated nitrate levels. Use of chloramines for disinfection greatly increases the issue. Water departments that use chloramines are required to closely track and report nitrate levels.
3. Boggles my mind that experienced fish keepers don't understand the nitrification - denitrification cycle. No wonder so many still have problems keeping fish.
Nitrate is NOT food for nitrifying bacteria, it is their waste product. Nitrate is consumed by DEnitrifying bacteria which live in anerobic to anoxic environment. It is NOT recommended to attempt to keep anoxic zones in a fish tank. [insert emoticon for "DUH"]
1. Nitrate does not kill fish in levels found in aquariums.
2. Many private wells and public water supplies have elevated nitrate levels. Use of chloramines for disinfection greatly increases the issue. Water departments that use chloramines are required to closely track and report nitrate levels.
3. Boggles my mind that experienced fish keepers don't understand the nitrification - denitrification cycle. No wonder so many still have problems keeping fish.
Nitrate is NOT food for nitrifying bacteria, it is their waste product. Nitrate is consumed by DEnitrifying bacteria which live in anerobic to anoxic environment. It is NOT recommended to attempt to keep anoxic zones in a fish tank. [insert emoticon for "DUH"]
Edited by mikez, 14 June 2014 - 12:18 PM.
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