Bizarre Readings From New Tank. Any Suggestions?

[Ddraig]

Hi all,

I have found all your advice v helpful in the past. I have a series of water parameter readings that I can't explain, but maybe someone clever can.....

I have a small 32l starter tank which is fully cycled and stable with 2 adult platy and a number of small fry. Usual parameters: pH 7.4, ammonia 0, nitrite 0, nitrate <20.

I purchased a second hand 180l tank from eBay and aquarium gravel from lfs. I washed the tank out with water (?had previous owner cleaned with something), washed gravel with tap water ++ and set tank up. It has I large piece bogwood (new), gravel, stones, 2 plastic and 2 live plants (all from small tank). Water was dechlorinated tap water. I had planned on running new filter supported by the old cycled small tank filter in tandem.

The new tank parameters were pH 7.6, ammonia 0, nitrite >5, nitrate 5. I rechecked with same results.

Any ideas where my nitrites have come from? A50% water change has made no appreciable difference.

Any thoughts or suggestions?

Thanks in advance,

James

 

[eaglesaquarium]

It would seem like the AOBs have transferred fine, but the NOBs are recycling... When your nitrites are that high, only a 95+% water change is goign to help. Lower the water until the fish can just barely swim upright and refill with temp matched dechlorinated water...

The NOBs should come back in a little while... just keep an eye on the stats and be ready to do a water change at the drop of a hat.

 

[CezzaXV]

I would agree with what eagles said.

In regards to the nitrites not seemingly dropping after a 50% change, that would mean the nitrites were at least 10ppm, as you changed half and still had greater than 5.

Whenever I get detectable anything, I always do as big a water change as I can, regardless of how bad the reading seems, because readable anything in ammonia or nitrite is bad.

 

[Ddraig]

Thanks eagles and Cezza,

What confused me is how the nitrites got so high as the tank was new treated tap water and gravel / stones plus 2 established plants. I don't have any fish in yet - they are staying in their happy cycled tank until the big tank is stable.

I don't really understand where the ammonia has come from for AOBs to metabolise!


James

 

[eaglesaquarium]

I'm guessing you have chloramines in your tap water, decaying plant material or some very interesting tap water...  I'd test it, with the dechlorinator you are using.

 

[sadguppy]

How old are your tests and were the tubes properly rinsed out? Have you re-tested to be sure? Can you see signs of distress in your fish?

I did a hasty 3/4 tank change on my 200l following a duff test, it was only upon re-testing the pristine waste water I realised it must have gone wrong some where along the line!

Even if it is a proper reading, in my experience nitrite eating bacteria are quite easily knocked out but quite quick to re-establish so a few days of big changes and it should be fine.

 

[Ddraig]

Thanks guys.

The good news is there are no fish in the tank and won't be until all sorted.

So, after the above readings I did a 95% water change and refilled with dechlorinated ( bio active tap safe) water. The nitrites at this point were 0.25 ppm (API kit).

At this point the only things in a recently cleaned (water only) tank were:
Air stone
2 live plants
3 plastic plants
I rock cave
8 large stones ( washed)
1 piece bogwood
Filter

24 hours later the nitrites were >5ppm again! Ammonia is still 0....

The real plants are now in a tank of their own, the bogwood is in a bucket and the stones in another. I plan on monitoring each to try and workout whether they are leaching from somewhere.

Could there be a contaminant that is high in nitrites?

All help gratefully received!



James

Sorry Sadguppy - in answer to your other questions:

Tubes rinsed
Tests less than 9 months old and giving normal readings on other tank
Tap water nitrite free but can test for chloramines

James