Nitrite levels 2

[Conduit7]

tank is 6 weeks old, been having nitrite levels of 3 with strips. Api master test kit came today. Been doing partial water changes every 3 days. Today tested amonia 0, ph 7.6, nitrite 2, nitrate 0. 36 gallon bowfront live plants, manzanita wood, rocks. Have 6 harlequin rasboras, 6 neon tetras, 3 kullie loaches. Very hard water in Las Vegas use prime and partial r/o water. Cycled the tank with 3 black mollies, gave them away when they started eating my plants. Local fish store not chain store said tank was cycled at 3 weeks ? Asked them about nitrite levels they told me not to change water in my tank for 1 month. 36 gallon bowfront, fluval 70 filter, 150 heater, running bubbler . New to fresh water.

 

[Byron]

First, it is nitrite (with the "I") and not nitrate you are referring to, correct? [We always ask this, as many do get them confused.]

How did you cycle the tank, meaning, what ammonia source if any, or was it just with three fish?

The store is not giving accurate advice...there is never a situation where water changes should not be done for a month when fish are present. When ammonia or nitrite is present, you should change as much water as you can every day until both are zero. But I do not understand nitrite being at 2 ppm...the fish would be dead if that were the case. It is 2.0 ppm...and not 0.2 ppm?

Plants can save you through this...can you post a photo so we can see the plant species and number?

 

[Colin_T]

Check your water supply for pH, ammonia, nitrite and nitrate. Post results here if they are not 0, so we can check and comment.

As mentioned by Byron, if you have fish in an aquarium with an ammonia or nitrite reading, you should do water changes to dilute them.

If you are cycling an aquarium with fish in, you want low levels of ammonia and nitrite so the beneficial bacteria have something to eat. However, once the tank has finished cycling and is established, you want the levels to be 0.

You can have high ammonia or nitrite readings and still have fish that don't die. Ammonia is toxic in alkaline water (pH above 7.0) and nitrite is toxic in acid water (pH below 7.0). So depending on what the pH is will determine how safe it is for the fish. A pH around 7.0 is best if you are having ammonia or nitrite readings. your pH is 7.6 and nitrite should not cause problems at that level.

Aquariums can take anywhere between 2 weeks and 2 months or longer, to cycle and for sufficient beneficial bacteria to develop to keep the ammonia and nitrite levels at 0. 3-4 weeks is an average estimated time shops give you so you don't go home thinking this could take 3 months.

You can do 50% water changes to dilute the nitrite. bigger water changes are generally better for diluting harmful chemicals.

How often are you feeding the fish?

Mollies need some plant matter in their diet. They like algae but if there is no algae in the tank they will graze on plants. They don't normally do too much damage to plants and if they do chomp them up, you can add plant based fish food (vege flake) to their diet to reduce the damage they do.

 

[NickAu]

Mollies love blanched zucchini medallions, cucumber medallions and shelled cooked peas. They also love spirulina based pellet or flake.

 

[Byron]

You can have high ammonia or nitrite readings and still have fish that don't die. Ammonia is toxic in alkaline water (pH above 7.0) and nitrite is toxic in acid water (pH below 7.0). So depending on what the pH is will determine how safe it is for the fish. A pH around 7.0 is best if you are having ammonia or nitrite readings. your pH is 7.6 and nitrite should not cause problems at that level.

Do you have a source for the comment that nitrite is not toxic in basic (above pH 7.0) water? I do not believe this is correct and would like to check it if there is some reliable source saying it.

 

[Colin_T]

I red the info in a book or scientific paper about 20yrs ago, sorry can't remember what it was in but I thought it was bizarre too, but apparently they did research and found it worked like ammonia in alkaline water, but with nitrite in acid water.

 

[Essjay]

From a 2005 paper http://www.vri.cz/docs/vetmed/50-11-461.pdf section 4.2.5 - the effect of hydrogen ions (ie pH) is still uncertain.
This paper does state that earlier "contributions to the literature on this subject" failed to investigate the effect of other anions present, and that they often used pH well outside the levels found in nature. They do comment that the effect of pH is minute within the pH ranges found in nature - which will be the same pH ranges found in our fish tanks.


Presumably, other 'contributions to the literature' include things like these:

A 1981 paper abstract http://www.nrcresearchpress.com/doi/abs/10.1139/f81-054?journalCode=cjfas says that nitrite toxicity in rainbow trout is pH dependant though I can't access the full paper.

A 1978 paper abstract http://www.nrcresearchpress.com/doi/abs/10.1139/f78-132 says that for juvenile steelhead trout, increasing pH from 6 to 8 decreased toxicity by a factor of 8 for smaller fish - but interestingly they also claimed that toxicity was deceased as hardness increased, and we know that generally speaking high pH is associated with hard water.

 

[Byron]

Essjay beat me to it.

I emailed a friend of mine who is very much up on water chemistry, and he gave me the same first link that essjay posted. Which agrees with my own research a few years ago when I was writing an article on bacteria for another forum. I asked for the source because once-held views can be shown inaccurate as scientific study progresses, but that hasn't occurred with this topic.

As far as aquarists are concerned, at any pH we are likely to encounter, nitrite is toxic at any level above zero. Fish readily absorb nitrIte from the water and it combines with the hemoglobin in their blood, forming methaemoglobin. As a consequence, the blood cannot transport oxygen as easily and this can become fatal. At 0.25 ppm nitrite begins to affect fish after a short period; at 0.5 ppm it becomes dangerous; and at 1.0 ppm it is often fatal. These numbers are general of course, as various factors can impact things, as it points out in the linked article in the above post.

It is true that ammonia becomes ammonium in acidic water, and ammonium is considered basically harmless.

 

[Conduit7]

Thank you everyone for feedback. Tank was not cycled as I suspected. Nitrites now at zero. I feed 1x a day. Plants Java ferns, lace Java fern, dwarf lily, anibius.