My Nitrates dropped w/o a water change...?

[Axis of Weasel]

whats going on?

I'm cycling my tank and my nitrates dropped from 50ppm to 10ppm in one day and I didnt change the water. I didnt do anything different!

[Lady Hobbs]

I had the same thing happen. Mine went from 80 to 40 to 0. And my tank had a perfect cycle. I did the large water change anyway but having 0 nitrates is pretty common for my tanks.

[Axis of Weasel]

I thought the only way to remove nitrates is to do a water change.

Does this mean my tank is done cycling? b/c i add ammonia everyday but my nitrites keep level and arent decreasing, and before today my nitrates were steadily increasing.

[Lady Hobbs]

If you are adding a bit of ammonia each day, and 24 hours later show a reading of 0 ammonia, 0 nitrites and have nitrates, you have cycled. But it has not finished yet until those nitrites drop to 0.

In all practical purposes, the nitrates should be very high and remain high until you do a water change to reduce it. I have no explanation what caused yours and mine to drop. It's happened on all the tanks I've cycled. My water is hard here and whether that has something to do with it, I haven't a clue.

[digital3]

Does your tank have live plants?

[Ocellatus]

I doubt plants can remove that large amount of nitrates, 50 to 10 in one day! or 80 to 40 then 0 !

I'm still thinking that if one has so many bio media in the filter (much more than needed), first aerobic bacteria will grow on the first part of media and they convert NH3 to NO2 and then to NO3. if there is enough food (ammonia) for them, they will grow up more and more till they consume all the water oxygen during the process. but we still have some more media, and if its enough, a complete colony of anaerobic bacteria will grow up. they do the reverse reaction, denitrification, convert nitrates to NO2 then NO then N2O and finally N2 gas that exits from the water.

thats just an idea, maybe a wrong one!

[plow]

I am gonna place a bet here and guess you are testing using API's solutions for nitrates, since you are having EXACTLY the same things happen with your rsults that I did. ignore what i have written below if you are not using API's liquid tests.

API's liquid nitrate tester only works for low concentrations... under 50 mg/l IMO

I have used their nitrate tester while cycling using ammonia and suddenly got a drop from around 40mg/l one day to 5 mg/l the next..

the problem was the API liquid test was completely wrong. I tested using API strips and seras nitrate test liquids and found my nitrate readings were well above 100 mg/l using these two. It made perfect sense, and yet API gave me values of 5 mg/l..

Does your sample turn slightly brown after the addition of just the first solution? Mine did, thats when I first suspected something weird was up.

What you can do is dilute your sample 50% or even 75% using *distilled* water or good quality tap water, and try again.

Do your test using the same method, read the value form your charts and multiply your answer by the corresponding amount you diluted.. a bit of math but atleast you'll be close to the true figure.

ie 50% = x 2
25% = x 4

I hope this helps as API had me scratching my head for days and I couldn't understand what had happened in my cycle. I was pretty disappointed to say the least, but now I use it again, knowing it is not good for high concentrations.

[Axis of Weasel]

Hi,

I am using the API (liquid) test kit. After I add the first Nitrate liquid, the tube remains yellow, not brown though. If you're right, it's strange how the test color card goes up to 100ppm but the test bonks out at 50ppm.

I'll try your method tonight and see what happens

thanks!



I am gonna place a bet here and guess you are testing using API's solutions for nitrates, since you are having EXACTLY the same things happen with your rsults that I did. ignore what i have written below if you are not using API's liquid tests.

API's liquid nitrate tester only works for low concentrations... under 50 mg/l IMO

I have used their nitrate tester while cycling using ammonia and suddenly got a drop from around 40mg/l one day to 5 mg/l the next..

the problem was the API liquid test was completely wrong. I tested using API strips and seras nitrate test liquids and found my nitrate readings were well above 100 mg/l using these two. It made perfect sense, and yet API gave me values of 5 mg/l..

Does your sample turn brown after the addition of just the first solution? Mine did, thats when I first suspected something weird was up.

What you can do is dilute your sample 50% or even 75% using *distilled* water or good quality tap water, and try again.

Do your test using the same method, read the value form your charts and multiply your answer by the corresponding amount you diluted.. a bit of math but atleast you'll be close to the true figure.

ie 50% = x 2
25% = x 4

I hope this helps as API had me scratching my head for days and I couldn't understand what had happened in my cycle. I was pretty disappointed to say the least, but now I use it again, knowing it is not good for high concentrations.

[plow]

Hi,

I am using the API (liquid) test kit. After I add the first Nitrate liquid, the tube remains yellow, not brown though. If you're right, it's strange how the test color card goes up to 100ppm but the test bonks out at 50ppm.

I'll try your method tonight and see what happens

thanks!

my test card goes up to 160.. so maybe they have realised their mistake in these kits and brought the scale down a bit..

'Sera' brand test solutions use the same technique I mention about diluting the sample, and then testing until you come into the right range.. Sera have obviously worked out that it is not accurate enough to do everything in one simple test, and that for different concentrations you different amounts of test solution, and that it is only accurate within a small range.

I am suprised I seem to be the only person here that has discovered this, so in some ways I am wondering if just somehow I have made a mistake.. but cant for the life of me think where. My API solutions even have the 2006 copyright label on them so they cant be that old. And I have shaken the living c r a p out of them to make sure there are no crystals forming in the solution bottles.

I am interested to see what results you get, and to see if it is just me that gets weird results from API's nitrate test.

report back when ya can :thumb:

[Axis of Weasel]

no luck. I used 1/2 tube of aq water and 1/2 tube of tap water and the results came up somewhere between 5.0 and 10.0 ppm.

oh yeah, i have a bunch of plants in the tank.

[Lady Hobbs]

It really had me scratching my head, too, the first time. I had no plants at all either so there was no where for those nitrates to just disappear to. I knew the test was good as it was new and I had gotten the high amount one day and then less the next until to 0. I never could figure it out and never bothered trying anymore. Everyone here told me it was impossible but it was right there in front of me. It remains a mystery but at least now there is someone else who has experienced the same thing so now I feel somewhat vindicated.

I would still do that water change after cycling tho just in case something isn't right.

[plow]

no luck. I used 1/2 tube of aq water and 1/2 tube of tap water and the results came up somewhere between 5.0 and 10.0 ppm.

oh yeah, i have a bunch of plants in the tank.


try with test strips... I wont beleive it is not true until you use some other method to confirm API's result is correct..

remember SERA brand does it in four stages, their first step is up to 40mg/L maximum, so even with a 50/50 dilution you are still only measuring up to 80mg/l before you need to redilute and try again.. you may even need to use a 20% 80% dilution to come within the range..

In the end my nitrate values were up around 200 mg/l (that suprised me) so there was no way that API tests could pick it unless I diluted it in the ratio of 1 ml sample and 4 ml water. After doing this the result came between 20 to 40 mg/l and so API tests confirmed that the test strips and thwe SERA nitrate tests were correct.

If you try with test strips and do a larger dilution like I did and still get weird results then I will admit I am wrong and that I am plonker for being so persistent and will join the scratching head club.

[plow]

It really had me scratching my head, too, the first time. I had no plants at all either so there was no where for those nitrates to just disappear to. I knew the test was good as it was new and I had gotten the high amount one day and then less the next until to 0. I never could figure it out and never bothered trying anymore. Everyone here told me it was impossible but it was right there in front of me. It remains a mystery but at least now there is someone else who has experienced the same thing so now I feel somewhat vindicated.

I would still do that water change after cycling tho just in case something isn't right.

Man noone beleives me...

there is a reason SERA do their nitrate testing in 4 stages.. it is hard to test for such a wide range of nitrates with one test.

nitrates dont just dissappear, if they did we wouldn't need to do water changes as often.

It doesn't need to be a mystery anymore.

[Lady Hobbs]

Heck, I believe you. Have no reason not to. Thanks for the explanations. I didn't even have those before.

[plow]

Heck, I believe you. Have no reason not to. Thanks for the explanations. I didn't even have those before.
ah cool Hobbs,

sorry I have been harping on abput this on various threads, and suspect some people are tired of hearing it and just think that a company like API wouldn't sell something that is slightly suspect.

I am certain about what I have found, and when I think my nitrate levels are low I will use API's solutions, and I trust the results. But twice I have had the same thing happen while cycling two tanks in recent times. the conclusion was simple, as soon as my nitrate values got to around 40 mg/l it was time to start using strips and/or seras test liquids, and/or dilute the sample to try with API.

It just didn't stack up, and the cooincidence here is that many people are scratching their heads for the exact same reason I was. How do nitrate suddenly drop using an ammonia cycle from 60mg/l one day down to 5 mg/l the next...

Its nice that some people are atleast open the idea, even if they are not fully convinced.

it just made so much sense to me, when I purchased seras liquid tests to check my results, that they did this test in four different stages to cover all concentrations up to 400 mg/l.. and not try to cover it all in one simple test.

I guess its a marketing thing for API, they will sell more kits if they make the test simple, and maybe people think sera's test are too hard, and for that reason people wont buy them.