New tank - high nitrates? Or is it?

[Jabes]

Hi guys,

I posted the other day about high nitrates after my cycle and thought that I understood everything. When we left the story I had done some substantial water changes and, according to my NT Labs test kit, saw low nitrates and went ahead and bought some fish. 4 nice mollies.
I threw my API liquid test away as I thought it was in error having used it incorrectly through the cycle, assuming that it was giving bad readings.
But I liked the API colours - the NT Labs light pink is hard to tesll - so ordered a replacement standalone from Amazon which has just arrived this evening.

I have been testing ammonia and nitrites since the fish have moved in, remained at zero, so happy with my bacteria.
Ran the API test kit and it looked like around 40ppm nitrates!

Having done some more reading on here decided to run a tap water test, and it too shows around 40ppm (live in south-east UK).
I repeated the NT Labs test from the tank, and it still shows low (5-10).

I have some paper dip tests which I have done, and also have done these against drinking water and these also show that there is not much difference between tap water and my tank.

So now I am very confused as what to do:
a) Am I going to have a problem with my fish?
b) How do I get an accurate reading - the API colour change between 40 and 80 is almost imperceptible
c) What should I do?

Confused of Canterbury

Best wishes
James

 

[Fishy_Dan]

We have ~30ppm nitrates in the tap water here in Orpington.
Do you have live plants? Apparently plants will use it as fertiliser. I don't think nitrates in the water are too much of a worry, unless they get up to near 100ppm.

 

[Jabes]

We do have some live plants, we could get a few more if it were useful. What tester do you use to be able to tell the difference between the higher values?

 

[Jabes]

NT Labs test (of tank water)

API labs test (of tap water) - this seems to have got a bit darker even (was about 30 minutes ago I did this test)

 

[Fishy_Dan]

I've got the API kit, it's not easy to tell the difference I agree. Mine is more orange and looks just a little darker than the 20 colour. Yours looks fairly consistent at around 40ppm would you say?

Just to check, do you do the rigourous shaking of the bottles as described in the instructions?

As long as amonia and nitrite are zero I wouldn worry too much. Carry on with weekly water change and things should be fine.

 

[Retired Viking]

I agree with @Fishy_Dan, I have moss ball in a couple of my tanks they are actually a form of algae and they absorb nitrates. Most other plants go for the ammonia 1st.

 

[Naughts]

Most tests say take the reading after 5 minutes. It is best to time this accurately for consistency. As you saw with the API the colour can continue to darken. Check the colour in natural daylight (by a window) where possible.

 

[Jabes]

Yes, I have been shaking the bottles (now) - that was my original mistake when I thought my nitrates were near zero. I will do some more readings tomorrow under natural light (of tap water and tank water) to see if I can tell the difference.
I'm reassured to know that although higher than optimum it's not too much of a concern - I guess the problem I have now is that I won't really be able to tell if levels are getting too high.

Are there any tests which are better at telling the difference in these slightly higher ranges? Perhaps I could dilute the tank water with some purchased distilled water in testing to try and get a better read on the real levels.

I wonder why the NT Labs test seems to read much lower...

 

[Essjay]

If you look on your water company's website for your water quality report, that contains nitrate. It will give the lowest, highest and mean values for a number of tests. The mean value will give you some idea of which tester is more accurate.

 

[Essjay]

I don't think nitrates in the water are too much of a worry, unless they get up to near 100ppm.

We now know we should aim to keep tank nitrate below 20 ppm. This makes it a bit tricky where tap water has a higher level. Besides using live plants, there are other things you could try such as a pozzani nitrate filter.

 

[Jabes]

Essjay,
Since I'm filling up from a garden tap anyway (to avoid my house wide water softener and any other interventions), the pozzani nitrate filter looks like it would be a really easy solution and could easily spend that much trying to find in-tank ways to solve the problem. Better to solve it at source! Have ordered one and will see what difference it makes.
Family think a moss ball is a good idea as well, now to try and find a good UK stockist!

 

[Essjay]

Glad to hear you are not using water from a water softener

Other members have used pozzani filters so they'll be able to help you if you need it.

 

[Jabes]

Pozzani filter arrived - service from them exceptional - water through the filter comes out at 0 nitrates. pH seems lower compared to my tap water (6.5-6.8) but tank is running a bit high anyway (perhaps the rocks or the oxygenation bringing it up) so will just keep an eye on it to see if it affects overall tank pH after a few changes.

I'll just change 20% each day for a few days so as not to give the fish too much of a shock and keep an eye on the pH.

Thanks for all your help!