Why Are My Nitrates So High?

[ShinySideUp]

My Master Test Kit shows my nitrates are up there in the 'really rather red' end of the range so above 80ppm and always have been.

I have a lightly planted tank of some 220 litres. My Ammonia and nitrite read zero, pH is low (Master Test Kit indicates yellow so at least as far down as 6.0). I change 30% of my water weekly and my tap water has a pH 7.4 or thereabouts and has 10 ppm nitrate.

I have:

6 clown loaches size small to medium-small
4 diamond tetras
1 small BN catfish
1 siamese algae eater
3 small cory's
and 5 kuhli loaches

I'm certain I'm not over-stocked.

I also have a well-planted 120 litre tank with stats exactly the same, I also change 30% of the water weekly.
In this tank I have only:

4 very small zebra loaches (no more than 1 1/2 inches as they are quite new)
16 black phantom tetras

So this is nowhere near over-stocked.

I'm not losing any fish apart from four cory's in the last six months but they were eight years old anyway.

But why are my nitrates so high?

 

[FishFanatic04]

IF your tap water only had nitrates at 10 ppm then one of these are possibilites:

1: You are not changing enough water. {I would do a very very large water change and see if your nitrates are lower by next week then the normal. YOu may have a buildup that you aren't removing by only doing 30%}

2. You are over stocked.

3. Something in your tank is producing a large amount of extra ammonia and it's then causing high nitrates.

4. other stuff.

I wasn't saying that you are over stocked though.

 

[tomtomtom1230]

IF your tap water only had nitrates at 10 ppm then one of these are possibilites:

1: You are not changing enough water. {I would do a very very large water change and see if your nitrates are lower by next week then the normal. YOu may have a buildup that you aren't removing by only doing 30%} Most likely!

2. You are over stocked. Definitely not. Check your filter though, is the flow still good and strong?

3. Something in your tank is producing a large amount of extra ammonia and it's then causing high nitrates. If I had to point fingers, it'd be at your BN pleco and your SAE.

4. other stuff.

I wasn't saying that you are over stocked though.

See above.

 

[fenny666]

Think of it like this.
Let's assume for simplicity your nirtate is at 90ppm and your tap water contains no nitrate whatsoever(of course it does but it's easier to illustrate).You change 30% of the water.Thereby removing 30% of the nitrate giving you a new reading of 63ppm (90ppm - 27ppm).All the while your system is producing more nitrate and factor into this the level of nitrate already in your tap water, as you can see as regards nitrate removal your pretty much flogging a dead horse.
It would appear you are ,at best,maintaining a level as opposed to reducing it.
I would check your tap water.My tap water is high in nitrate so I use a nitrate filter I bought online which goes under my sink.Whilst it doesn't remove all nitrate it reduced it significantly.
Follow this with increased frequency water changes until the nitrate reaches a desirable level.Also be aware of how much you feed your fish. I would suggest a minimal approach while trying to bring the nitrate down.

 

[ShinySideUp]

I would check your tap water.

Tap water is 10 ppm.

Did a 50% water change today and nitrates are down to about 80ppm. I shall cut down on my bottom-feeder food putting in only a little flake for my tetra's for a short while and see what happens. By coincidence I have just tripled the number of plants so that may soak some of it up too.

 

[FishFanatic04]

Do a few more water changes and get the nitrates down to 15-20. At that point your weekly water change should keep your levels lower.