High Nitrate! Why?

[stanleo]

Hi All,
 
So I broke down today and bought a Liquid test kit. API Freshwater Master Test Kit. Until now I have been using strips and finally took you alls advice that they are useless and figured this would last longer anyway.
 
I tested my 29g community tank and these are the results.
 
pH 6.4
Ammonia 0
Nitrite 0
Nitrate is either 40 or 80 ppm. the color is too close for me to call.
 
I am over stocked with 5 von rio tetras, 5 neons, 4 peppered corys, 1 dwarf gourami, 1 dojo loach, and 3 whisker shrimp. I do 30% WC weekly and just did one yesterday. Do I need to change more water? The tank is heavily planted so I don't really understand why my nitrate is so high. The tank has been running for over 18 months. Fish look and act fine but I did lose one neon last week.
 
I also tested my 10g shrimp tank and those results are good.
 
pH 6.4
Ammonia 0
Nitrite 0
Nitrate is 20 ppm.
 
But that tank only has about 30 or so RCS most of which are babies and 3 endler's livebearers.
 
What should I do?

 

[Livewire88]

Well if it was me I wouldn't worry about your NitraAte level, 80ppm wont bother your fish at all and your plants will be feeding off the NitrAte and be healthier for it. 
 
Just stick to your water change regime and all should be fine 

 

[Meeresstille]

Sometimes Nitrates can go up if too much organic matter remains on the substrate. It can be quite difficult to get all the fish waste if there are so many plants, good thing is eventually the waste breaks down and becomes plant food. Having too many fish in a tank can cause their waste to become a problem for the tank too. It is good that you are testing your water and you have the choice to make changes to find the right balance for you and your tank.

 

[attibones]

Honestly it wouldn't hurt to increase your water change percentage.
 
What is your tap water nitrate level? Some regions have higher than others. It could be that you have some nitrate in your tap which could contribute to the levels in both tanks (although the smaller one is fine). It's not much to worry about though. If you get it over 100 ppm, then you should be concerned.

 

[TwoTankAmin]

I would bet the nitrate readings are not all that accurate. I have not used any of mine over the years after cycling my very first tank (I have replaced test kits three times in the last decade because they got old before they got used up.) Inverts normally don't do will with nitrates, if yours seem fine that is a good clue. Corys also are not happy w/ nitrates, so watch them as well.

 

[stanleo]

Thanks guys that really helps. I think I will up my water change to 40% a week.

 

[snazy]

I would bet the nitrate readings are not all that accurate. I have not used any of mine over the years after cycling my very first tank (I have replaced test kits three times in the last decade because they got old before they got used up.) Inverts normally don't do will with nitrates, if yours seem fine that is a good clue. Corys also are not happy w/ nitrates, so watch them as well.

 
That seems about right. I barely use the nitrate test because it seems to be all over the place, very inaccurate and probably wrong.
If you have a planted tank, be happy, free nitrAtes I pay for that stuff..
 
If you are worried, clean the filters more often and do 50-ish % water changes weekly. In a planted tank the debris in the substrate can be beneficial to your plants. I surely wouldn't deep siphoning it but you can give it a very light surface clean...

 

[DoubleDutch]

You could feed less probably, and do more waterchanges. That's the biggest nitrate-cause. To my believe 80 isn't any good for fish (above 50 isn't).

 

[CJH0825]

+1 DoubleDutch
 
I read a article that anything below 40ppm is acceptable, But over that is not good.

 

[snazy]

+1 DoubleDutch
 
I read a article that anything below 40ppm is acceptable, But over that is not good.

 
You nitrate test maybe showing you 40ppm when you have 100ppm or showing 100 when you have 20ppm, it's that inaccurate, so it's questionable what the OP levels are unless tested in a laboratory. In a well planted tank nitrAtes could be anything. Not sure if Stanleo doses any macro ferts that contain nitrAtes as well...

 

[TwoTankAmin]

OK- here is the skinny on nitrate tests- its in how they work. Reading nitrate is very difficult, so the method is to first convert the nitrate into nitrite and then to read that. And the potential problems with should be obvious- they will most likely occur during cycling.
 
To have a decent shot at getting an accurate nitrate reading you should also test for nitrite at the same time. That way you subtract the nitrite ppm from the nitrate ppm to get the amount that is actually nitrate.
 
Of course, if you have more nitrite than nitrate, testing for nitrate is a waste. If one is cycling a tank don't bother testing nitrate until your nitrite has peaked and is coming down.
 
And then there is the issue of what scale the kit measures vs what amounts we are warned can harm fish. So this makes things all the more iffy. If one tests using a kit that measures nitrate-n vs total nitrate you git vastly different readings.
 
20 ppm of nitrate-n (the measurement scale usually used by science) is equal to 88 ppm of NO3 (measureing total ions). The conversion factor is NO3 = NO3-N * 4.42664 (I rounded to 4.4). What this means is depending which scale one is referring to, saying 20 ppm nitrate is the level above which one should change water and 80 ppm is the level can both basically be correct. Its like measuring this line ______________ in inches vs centimeters. Its the same length either way, just a different scale.