Determined

So, after doing a fishless cycle of my 20 gallon tank, I added two dwarf gouramis two weeks ago. After a week I was getting amonia readings of slightly higher than zero (darker than zero, lighter than .25 on the API color chart), which I thought was kinda odd, but I let it go. The nitrites were at zero and the nitrates were at around 5 for that week.

Cut to week two and it gets really wierd. ammonia shoots up to .5ppm, nitrites stay at zero and the nitrates are at a steady 10ppm. I have not added fish during this week and, after doing two 30% water changes on thursday and Saturday, the ammonia readings have shot back up to .5ppm within 24 hours.

I don't understand it. Has this happened to any of you? I have not changed the bioload at all. I was planning on adding some cory cats this weekend, but with the high ammonia readings, I decided to wait until the tank stabalized. And, to cut some of you off at the pass, I am religious about not overfeeding my fish. Two flakes at a time until they are gone for abot 3-5 minutes or so at each feeding. I give them one freeze dried bloodworm each every now and then as well.

Chief_waterchanger

Does the tank have substrait in it? Make sure to stir the substrait through half the tank one week with a waterchange then the next week do the other half, it keeps gasous bubbles from getting too large under the substrait, and stirs up any extra fecal matter, food, etc.

Determined

I have been stirring and vacuuming the substrate. I just got the Lee's aquarium vac (just like the python, but a little cheaper) and it comes with a very handy gravel cleaner nozzle. Thaks for the tip, though, chief.

Chief_waterchanger

Sorry I have no idea what is going on then... maybe someone will come up with something. Its very very rare to have false endings of the cycling (the numbers hitting 0 and then coming back up), but it does happen. It is very hard to diagnose things without being a first-hand experiencer of the issue at hand.

Again, best of luck.

Butterfly

Check your tap water- this is how you do it. Run a glass full of water, let it set for 24hr to gas out, then test it for ammonia, Nitrites and Nitrates. You might be surprised. Let us know what you come up with.
If thats not it, try vacuuming only half of teh substrate at a time, you maybe pulling too much beneficial bacteria out before it catches up to the bioload of the two gouramis.
Carol

bhcaaron

How long did the tank take to cycle?

Could it be the tank acclimating to the new bioload?

Determined

Thanks for the tips, everyone. I will definitely test the tap water, as you suggest, butterfly. Never thought about the tap containing ammonia, but I bet it is playing a role.

bhcaaron, the tank took 27 days from the day I first put ammonia into it until I had my first double zero reading for ammonia and nitrites and a 5 for nitrates. I waited an additional 6 days until I added the fish. I was wondering about the difference in bioload myself, but what is odd to me is that the nitrites have stayed at a consistent zero while the ammonia has shot up. Weird that there would be enough bacteira to convert the nitrites but not enough to convert the ammonia.

jeme

If I test my aquarium water right after a water change, I get a slight measurable amount of ammonia. But, my local water contains chloramines. Adding water conditioner neutralizes the chlorine and ammonia but leaves ammonium, which registers as ammonia but is not harmful. Next day, ammonia back to 0.

Also, sometimes I loose track of the number of drops (d'oh!) I've put in and wind up with a strange reading... Starting over takes care of that...

Julie

bhcaaron

For the experts:

Is it possible that something made the amonia eating bacteria die off but didn't affect the nitrite eating bacteria?

Butterfly

The additional bioload would naturally show up as ammonia first. Then the ammonia converts to Nitrites and then to Nitrates. Maybe the ammonia just hasn't converted to Nitrites yet.
but I'm betting on the tap water.Water companies frequently add extra stuff to clean pipes or kill bacteria when there has been less water fall. So I'm curious about your tap water.
Carol

Determined

It makes sense that it is coming from the tap, and that it is ammonium. I mean, with readings that high for 4 consecutive days, you would think that the fish would act stressed. they haven't though. they are happy as ever.

BTW, while I haven't been able to test the tap water yet, since I started this thread, I have not performed any water changes and my latest ammonia reading (today) was 0 with 0 nitrites and nitrates of 15ish.

Butterfly

Sounds good After you do your next water change check it. If there is ammonia there we will know pretty much it's the tap water. If not then we will know the bacteria hadn't caught up with the additional bioload at the last testing.
does that make sense
carol