# nitrates/w/c's



## TrashmanNYC (Dec 10, 2007)

I did a 50% w/c this afternoon.......before the w/c the nitrates were around 10-15ppm.........i checked them again tonight and it seems to be about the same.......is this normal, or is there something wrong?

Robb


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## Toby_H (Apr 15, 2005)

I read online all the time that if you have 50ppm nitrate and do a 50% water change you will have 25ppm nitrate...

But that's not what I experinece with my tanks. There are too many other factors involved.

Did you clean the filters? How thoroughly did you clean the substrate? Did you move everything and clean under/behind all the decor? I'm sure I'm overlooking more than I'm mentioning as well.

The water is still 'fresher' after doing the water change. Your fish still appreciate you for it 

heck 10~15 ppm isn't bad at all to begin with....


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## smellsfishy1 (May 29, 2008)

Is the test kit reliable/not expired?

If it is accurate you may want to check your tap water or is the tank really dirty or is/are the filter(s) dirty?

If that isn't the source you may just need to do another 50% w/c within a couple of days. This worked for me when I was trying to drop my nitrates.

I found that nitrates can be stubborn and it takes a valient effort in many areas to get them down and keep them down.

Feed less and water change more. 
Also, do not let anything rot in the tank and that means not only food but fish. 
They can sometimes go unnoticed and often get pushed in the smallest cracks and holes.


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## Number6 (Mar 13, 2003)

Toby_H said:


> I read online all the time that if you have 50ppm nitrate and do a 50% water change you will have 25ppm nitrate...
> 
> But that's not what I experinece with my tanks. There are too many other factors involved.


 

normally, a 50% water change MUST cut your ppm in half... by definition!

Either, you are not doing a 50% water change after all, or your nitrates were not really at 50ppm. 
I'd guess it's the latter.

Perhaps nitrates are stirred up by your cleaning process from canister filters or substrate?
I'd say it could be likewise for Robb. If nitrates aren't in your tap water, then the tank isn't truly at 15ppm when you get that reading.


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## Fogelhund (Dec 3, 2002)

Number6 said:


> normally, a 50% water change MUST cut your ppm in half... by definition!
> 
> Either, you are not doing a 50% water change after all, or your nitrates were not really at 50ppm.
> I'd guess it's the latter.
> ...


There must be nitrates in the tap water? Try testing that.

Or, the substrate was stirred up?


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## TrashmanNYC (Dec 10, 2007)

i changed out the floss on the HOB a few days ago and the canisters have only been running for about 2 weeks............
i also vacuumed the top of the sand and "raked" it with my fingers..........
and my tap tested at 0.......


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## Number6 (Mar 13, 2003)

*TrashmanNYC*

Let's start eliminating variables then...

Test 1: Take Large Sample of aqaurium water, put in bucket. Test Nitrate today, then tomorrow.

Test 2: Take a Large Sample of aqaurium water at 50% volume to the first and add 50% tap water, put in bucket. Test Nitrate today, then tomorrow.

Test 3: Do a 50% water change again on the tank by water volume, NOT height of water on the tank. Test Nitrate today, then tomorrow.

The above will tell you whether your test kit is working, and where the nitrates are coming from...


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## TrashmanNYC (Dec 10, 2007)

Number6 said:


> *TrashmanNYC*
> Test 3: Do a 50% water change again on the tank by water volume, NOT height of water on the tank. ...


how do i do that? with 5 gallon buckets?


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## Number6 (Mar 13, 2003)

that is what I use if I am trying to be precise on volume removed or added... the 5g water jugs that drinking water is often sold in are pretty convenient as well.


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## TrashmanNYC (Dec 10, 2007)

how do i know the exact volume of water that is in the tank?


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## Number6 (Mar 13, 2003)

TrashmanNYC said:


> how do i know the exact volume of water that is in the tank?


Oh... When I set up a tank, I make sure to measure the volume of water it takes to fill it up. It's such an automatic thing for me because it helps with dosing meds, water conditioner, filter selection, etc. If you don't do that though... that presents a small problem.

If I were to suggest that you pull out rocks and decorations and measure the height of the substrate, is that something you could do? or is that a bunch of work?


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## TrashmanNYC (Dec 10, 2007)

it would actually be quite a bit of work...... 
http://triton.imageshack.us/Himg389/sca ... &ysize=480

im thinking about doing it though because im not sure if my abn's are still allive or not.......one was about 2" but the other three were really tiny.......i havent seen any of them in over a week.......  
its also strange tho, b/c i have the same nitrate problem in my 20g tropical tank.......


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## Number6 (Mar 13, 2003)

Looks like it would be a fair amount of work! I'm guessing that using a measuring tape and marking off the half way point will be fine... with rocks, you'd actually be above a 50% wc and that would surely drop by at least 50%.

If the ABNs died, that might explain the nitrates... if your test kit is not very precise and hits 15ppm even if in a larger range then rotting bodies could be a culprit.

The only problem with that theory is if you are having the same problem on the small tank and no deaths...


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## Toby_H (Apr 15, 2005)

In regards to a 50% water change not always reducing nitrates by 50%...

I stated there are factors involved that impact the water... then I asked some questions that came to mind that may be some of theses factors, as well as pointed out I do not feel I listed every possibility.



Toby_H said:


> I read online all the time that if you have 50ppm nitrate and do a 50% water change you will have 25ppm nitrate...
> 
> But that's not what I experinece with my tanks. There are too many other factors involved.
> 
> Did you clean the filters? How thoroughly did you clean the substrate? Did you move everything and clean under/behind all the decor? I'm sure I'm overlooking more than I'm mentioning as well.


Collected waste in the filter is constantly biodegrading being converted into additional nitrates. So if you tested the instant the WC started... did the WC instantly... then instantly tested afterwards, sure the nitrates are cut by 50%... but as stated in the original post there were several hours between the water change and the second test... during which time nitrates were being "created"

Trashman... is it really worth all this work to address such small amounts of nitrates?

If so, keep in mind you only have to use the 5 gal buckets to measure water volume once, as long as you remember to mark the tank


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## Toby_H (Apr 15, 2005)

A further explanation of why 50% water change may not reduce nitrates by 50%...

If the waste the fish produces per day creates 5 ppm of nitrates per dayâ€¦ but the filter hasnâ€™t been cleaned in a while, it may have several weeksâ€™ worth of waste in it that is breaking down. Of course you would not multiply several weeks x 5 ppm to calculate daily increasesâ€¦ itâ€™s not that drasticâ€¦ but in addition to the waste being produced by the fish each day, there is waste in the filter breaking down into nitrates.

So if nitrates are 50 ppmâ€¦ and I do a water change at noonâ€¦ at noon:01 the nitrates will be (should be) 25 ppmâ€¦ but that evening itâ€™s possible for the waste in the filter to have broken down into nitrates and the nitrates will be above 25 ppmâ€¦ when the filter is disturbed (turning on/off; refilling the HOBâ€™s housing; priming; etc) this may move the waste around exposing â€œfreshâ€


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## smellsfishy1 (May 29, 2008)

I admire your efforts Trashman. 
You are a very diligent hobbyist.

Don't for a second think that 10-15 ppm nitrate is bad. 
That is excellent and you can hang your hat on that. :thumb:

As has been noted nitrates do not stop just because you did a water change. 
You just cut them down some and they go right back up.
You probably shouldn't dwell on it for yor own sanity.

Keep up the good work but don't get caught up in this number game.
You will be much happier when you realize your efforts exceed what is necessary.
I am sure your fish are super healthy and will continue to thrive.


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## Number6 (Mar 13, 2003)

kumbaya.... kumbaya... oh, wait, aren't we bonding around the campfire? :lol:

I was under the impression that Trashman just wanted to figure out what was up and not necessarily worried that anything was wrong with the fish...

Trashman... want to clarify? 

Personally, if my nitrates went from 7.5ppm to 15ppm in a single day, I'd want to know what was going on... in any of my tanks, that would indicate something rotting! Nitrates in my tanks typically climb at around 2ppm per day... or at least that was the average rate back when I measured frequently.

My 2 cents.


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## TrashmanNYC (Dec 10, 2007)

Thanks, im not losing sleep over it..i was just curious if something seemed wrong or if it was normal........ill just keep an eye on it and see how it goes.......
im using the API Freshwater Kit btw.......

Robb


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## TheFishGuy (Apr 21, 2005)

I do one third water changes once a week. Every Sunday. What are nitrates again?


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## TrashmanNYC (Dec 10, 2007)

TheFishGuy said:


> I do one third water changes once a week. Every Sunday. What are nitrates again?


it was about 15ppm before the w/c and about the same a few hours later...


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## TheFishGuy (Apr 21, 2005)

Mine usually stays the same after water changes also. At the time of all my testing of all my tanks I just bought an API test kit out of curiosity. My problem is in an 800 there's usually something that rotting and it's impossible to find it... After a bit the other fish take care of it.

Also, I was just making an attempt at being funny. My nitrates hover right around 15 at all times unless a tank misses a week which doesn't happen very often.

As for water changes, ideally a water change should be done on a daily basis. Which could easily be achieved by installing an automatic water changer. It's better to change small amounts often than large amounts every so often in my opinion. That's not always easy to do though.

I would definately try the bucket test though. I've never done that, but then again I'm not a big water tester to begin with... That being said (or typed if you will) I'll just sit back and watch the conversation unfold


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## smellsfishy1 (May 29, 2008)

If nitrates are at 15 ppm and you do a 50% water change that brings it down to 7.5. 
Agreed?

Now the test kit uses different shades of red so now things get difficult. Let's say the kit shows a 10 ppm reading since you can not say what it truly is with confidence.

Now if your tank produces 2-5 ppm nitrates in one day or the margin of error (meaning trying to guess which shade of red you have) is 2-5pm you now have a nitrate reading of..... you guessed it, it looks like you still have 15ppm.

If you let the nitrates get to 100 ppm and did a 50% water change you could easily notice the difference in shades of red and conclude that you now have 50ppm.

So also take into consideration the starting point here.

What is the true difference (especially being vague shades of red)between 5 and 10 ppm or in Trashman's case 15ppm or whatever he is shooting for?

The problem here is testing. There are many ways for the results to become unreliable.

Human error, equipment, and the continuous production of nitrates are most likely the reasons you see little or no change.


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## TrashmanNYC (Dec 10, 2007)

its not quite the 10ppm color and its not quite the 20ppm color, its kind of in the middle so im just guessing its about 15ppm........


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## smellsfishy1 (May 29, 2008)

That is what I mean. The accuracy factor that seems to be the Achillesâ€™ heel to a possible solution.

I am not questioning your judgement Trashman, you most likely are dead on with what you see, just saying that test kits can't be considered 100% accurate or full proof.

The kits are nice because they give us a close readings but definitely not exact.

As a matter of fact, my nitrates are red just like yours, like 10 red or 15 red or 20 red! :lol:


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## TrashmanNYC (Dec 10, 2007)

i hear ya..... 8)


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