Nitrite Detectable - cannot find cause, established tank

[W1368]

This is a well established tank (an old Juwel Rio 125, T8 lighting).

The aquarium is heavily planted with a good growth rate, with addition of C02. Using EI for ferts.

The fish have been acting a little strangley recently, some have died over the past month. After testing the water I had found that the nitrite levels have been detecable, ammonia was not.

I think this may have been present for some time, I have not tested for nitrite for quite a while.

I change about 50% of the tank water weekly and the only visable algae only occurs on the older plant leaves (which I understand is due to the lack of lighting).

I'm using the internal Juwel Filter (with JBL nitrate remove bag, not Juwel sponge), the rest are just the blue sponges, I wash about 2 sponges every two weeks or so.

The only other thing I can think of is the pump, this has proberbly been running for around 5 years continusly and has never been replaced or cleaned (even though it should be possible to open up the pump for cleaning, it just isn't as its become far to stiff).

Would replaceing the pump (Currently the Juwel 600) with the Juwel 1000 be of any help or could it be somthing else? I do not nessercarily want to spend much on this tank, as its more cost effective to purchase a new aquarium than upgrading the lighting and adding a new external filter.

Cheers.

 

[G H Nelson]

Hi
Where do you wash the filter sponges?
How many sponges are there?
hoggie

 

[W1368]

The sponges are washed in siphoned aquarium water.

I have the following:
-Small amount of JBL white filter wool
-JBL Nitrate remover bag
-Fine blue Juwel sponge
-Juwel Biomax (just purchased last night), was told by shopkeeper this has larger area for bacteria. Not sure if its of any use but couldn't complain for £5.
-Juwel corse blue sponge

 

[scifficus]

You did something wrong while manipulating your filter and killed some beneficial bacteria. And your first configuration of media is was worst. To low on biological filtration.

 

[ceg4048]

Hi, this is just an opinion but nothing so far makes any sense. Everyone seems to jump to conclusions based on not-very-solid evidence as well as on fictitious assumptions:

So, fish were acting strange and some died...in a CO2 injected tank. No explanation of what "strange behavior" means has been provided.

A nitrite test kit was employed with a positive results. No mention of the test reading is provided.

On this basis it is concluded that the fish died of nitrite poisoning? That's it? An open and shut case?
There's no possibility that the fish acted strange and died due to CO2 poisoning??
No possibility of pathogen attack?
No possibility that the nitrite test kit gave false results?
When the fish were behaving strangely, was there an immediate massive water change and was there any change in behavior as a result?

Insufficient bio-filtration? In a heavily planted, well established planted tank? Highly improbable. Plants are biofilters. Therefore, lots of plants means lots of bio-filtration.

Also, what I find bizarre, and which may not be relevant, is that.a tank is being dosed via EI, and the hobbyists uses a Nitrate remover? EI adds massive quantities of Nitrate. That's the whole point of EI. Why would one use a Nitrate remover after spending well earned dosh on Nitrate powder? No one questions this?

I change about 50% of the tank water weekly and the only visable algae only occurs on the older plant leaves (which I understand is due to the lack of lighting)

FYI, light causes algae, therefore this conclusion is impossible. One needs to identify the algae in order to determine why it happens.

So there are a lot of questions that ought to be answered in order for troubleshooting to be effective. It's not a logical conclusion at all that one needs to suddenly add more filter media to solve this issue.

Cheers,

 

[W1368]

Thanks for the heads up.

The problems were due to a number of issues. I have taken out the nitrate remover from the filter, and replaced with extra bio media. Turned out that the bag was full of tiny particals that spread around the tank.

Upgraded the pump to 1,000lph. Lighting was reduced by a couple of hours - the water is now crystal clear and no algae can be seen anyware at all. I had experienced issues with brown diatoms but these have now cleared.

The reason for using the nitrate remover was after researching the information floating around the internet that high levels are a problem for fish, I didn't realize that it acually applies to high nitrates caused by waste rather than ferts.

Also seen that my plants are showing clear signs of deficiancy. I've just begun increased dosing.

Ammonia and nitrites have been undetectable for a while, although since posting I've had another dead fish, and last night decidied to remove another from the tank due to a case of severe dropsy.

As for the fish, I beleive the problem could be underfeeding and lack of the vitamins??? I have been using just a pinch of dried granule type things once a day. Will start using flakes, frozen fish food, blood worms etc throughout each week to give them something more varied.

Will wait a couple of weeks and then hopefully add further fish. Right now there is just a single fish for the majority of species I have.

 

[Katch]

I'd be most interested to know how many fish you are stocking. (Before the deaths)

When an established tank has nitrite readings and you haven't done anything funky to the filter - it usually points to an overstocking.

 

[W1368]

Roughly the following, cannot remember the exact list:
1 x Banded Rainbow
5 x Black widow tetra
4-5 x Glass tetra (now have 1)
4-5 Neon tetra (now have1)
3 x Rummy nose tetra
2-3 x Black Neon tetra
2 x Glowlight tetra
2 x Lemon tetra (now have 1)

 

[Katch]

I'd say that's skating on the edge of overstocked. You'd get away with it as long as your filteration and WC routine is spot on and feeding is kept to the minimum.

Another posibility is that you have a disease problem. Especially as you say you had to remove a fish with dropsy.

Tetra from the farms are notorious for having disease and health issues.

 

[W1368]

Ah,

Just tested again last night for Ammonia and Nitrite. They have become detactable again, but not as servere as before.

According to a TetraTest kit Nitrite is between 0.3 and 0.8 mg/l and Ammonia is between 0 and 0.25mg/l.

I know these test kits are usless in accuracy, but after testing the tap water it was a clear zero. Both the aquarium & tap water was tested twice with same results.

Could it be the plants that are showing severe signs of deficiancy causing this issue? The tank is heavily planted, and I'm thinking it might be easier just to take out all of the plants and start over :? The new growth appears acceptable but could be better.

I think I will hold back on adding new fish, I looked very closey last night and a small number of fish are showing some signs problems. One glowlight tetra and the neon are staying under cover and not really swimming around much, plus they are seem to be gasping slightly. They do come out during feeding.