High Nitrate Levels..?

[Asteria]

So got a new test kit. Got the Api freshwater master kit.

The first thing I do is test my water.
And find out I have rather high nitrate levels.
So I did my water change as planned.

Testings before water change:
Nitrite: 0ppm
Nitrate: 40ppm
Ammonia: 0.25ppm
pH: 7.6
High pH: 7.4

Levels after water change:
Nitrite: 0ppm
Nitrate: 10-20ppm
Ammonia: 0ppm

Shall I test it again for nitrates in a few hours ?

 

[Asteria]

So it's been over an hour since last testing
Nitrates are reading at 10ppm
Shall I do another water change?

 

[stanleo]

If you want your nitrates to be 0ppm, I would do a 50% WC and that should do it. However, most aquarium fish can and do live quite well in 10ppm nitrates and live plants use nitrates. I keep my nitrates as close to undetectable as possible in my planted tank and dose with liquid fertilizers. But I had a 29gl planted tank for a few years that always had 40ppm nitrates and my fish and shrimp were fine living in it.

 

[Byron]

You are OK below 20 ppm, but I would suggest a couple things to sort this out.  First, have you tested your tap water alone for nitrate?  Worth knowing if any are coming in via water changes.  Second, nitrates should remain steady at some level from week to week.  If nitrate is low after a water change, and significantly higher by the next one, there is something wrong biologically.  No matter when you test, the nitrates should be much the same from test to test, at least with the test kits we use.
 
Byron.

 

[Asteria]

Thanks guys
Well have been talking here and found out I have my nitrites and nitrates mixed up xD
And the 10ppm did increase to 40ppm on the test again the longer I left it.

This is fine since I have plants.

 

[Byron]

Thanks guys
Well have been talking here and found out I have my nitrites and nitrates mixed up xD
And the 10ppm did increase to 40ppm on the test again the longer I left it.

This is fine since I have plants.

 
Not sure if I am understanding.
 
Nitrite must be zero at all times.  Is this the case?
 
Nitrate must be stable, and should be kept below 20 ppm as the absolute maximum.  But it should not be increasing from water change to water change; if it is, there is a problem.  Live plants do not make increasing nitrates better.  Plants, plus water changes, plus having a balanced system biologically should mean consistent nitrate readings and at a low level.
 
Byron.

 

[Asteria]

No , I meant like I was getting them mixed up as in thinking nitrates must be at zero. but nirites are the ones that should be.

My nitrate levels are the same 40ppm or between 10-20ppm if read instantly. If left for 5mins it gets to 40ppm

 

[Byron]

No , I meant like I was getting them mixed up as in thinking nitrates must be at zero. but nirites are the ones that should be.

My nitrate levels are the same 40ppm or between 10-20ppm if read instantly. If left for 5mins it gets to 40ppm

Thanks for clarifying.  So that brings us back to the high nitrates, and I can assure you that nitrate above 20 ppm long-term is not advisable.
 
Have you tested the tap water alone, and if yes, with what result?
 
How often are water changes, and what volume of the tank water is changed at each?  What is the fish load, and tank volume?  Do you dig into the substrate at water changes (I know you have plants)?  Are you adding plant fertilizers, and any with nitrate?
 
Byron.

 

[stanleo]

The API kit does take 5 minutes to develope. I would do another WC tomorrow. 

 

[DeanoL83]

My nitrates are always between 20 and 40ppm no matter how regularly I do a water change.  I am getting more live plants in the next day or so (waiting on the delivery) in an attempt to reduce these, and also waiting for my frogbit to grow (as I heard these use nitrates really well).
 
Tested my tap water and it has nitrates at about 10-20ppm.
 
Is adding more live plants really the only solution that I have?

 

[Fishmanic]

how big is your tank?    What exactly is your stocking?   Perhaps you are overstocked.  Post the list of fish.