Quarantine Tank Cycling- Zero Nitrates

[blackhorse]

Over the past 4 weeks I have been cycling my 10 gallon quarantine tank with fish food. Everything seemed to be going as expected. Ammonia levels spiked followed by a subsequent lowering of NH3 and increase in Nitrites. Finally both Ammonia and Nitrites are at zero now but my Nitrates never increased and are also at zero. Should I recycle it using some other method?

[roka64]

What is in the tank, sand, rock, PVC?
What type of media, sponges or bioballs?
Did you have your water rechecked at your LFS? It is possible the test kit might be bad....

[blackhorse]

I only have pvc in the tank and I have a Maineland Biowheel 100 which I had off through most of the cycle. I think the test kit is ok because it works with my display tank.

[roka64]

The biowheel would have been the place the beneficial bacteria would have grown in. How high were your spikes? How long before you added the biowheel?

[blackhorse]

So I should have had the biowheel running through the entire cycle? I had it running for maybe the first week of the cycle. I didn't keep a record of what the levels were. Should I redo the cycle then?

Also, my display tank has been cycled for about 4 weeks now. Will it still be ok if I have to wait another 4 weeks in terms of nitrates, nitrite, etc levels.

[roka64]

You can probably just seed the biowheel in your cycled main tank. That would be a lot quicker.

[Kurt_Nelson]

Originally Posted by blackhorse

So I should have had the biowheel running through the entire cycle? I had it running for maybe the first week of the cycle. ...

I'm confused... you took your biowheel out after one week into the cycle? Did you just take the biowheel part out, and leave the rest of it behind. Did you still have the blue filter in it?

Reason for asking is that the ammonia and nitrites went somewhere obviously, and assuming you didn't do any water changes, they had to have been consumed by bacteria. Without the biowheel and blue filter, that bacteria wouldn't have had anyplace to live.

If you took only the biowheel part out and left the blue filter, then your bacteria is most likely in the blue filter.

Without really knowing what happened when, I'm afraid we can't really give ya good advice.

PS... regarding your display tank - if it's been cycled for 4 weeks and you haven't been "feeding" it anything to keep the bacterial population happy, then you may have another cycle when you add something. Once cycled, you need to keep introducing something that will give the bacteria ammonia to process.

[blackhorse]

So for my display tank maybe I should be adding some fish food once in a while?

For my quarantine tank I ran the biowheel for a couple of weeks and just unplugged it after that. I didn't think it mattered that I used the filter. Do you think that I can just run my biowheel now and the nitrates will show up?

[Kurt_Nelson]

So for my display tank maybe I should be adding some fish food once in a while?

Yes - the bacterial need an ammonia source to survive. If your tank has been without it for 4 weeks, I'd guess you'll see another cycle. Maybe someone else here has first-hand knowledge of how long a tank can go fallow before the bacteria die off.

For my quarantine tank I ran the biowheel for a couple of weeks and just unplugged it after that. I didn't think it mattered that I used the filter. Do you think that I can just run my biowheel now and the nitrates will show up?

I don't understand why you'd think the biowheel doesn't matter. If that's the case, why did you even use it to start with?

Putting the biowheel back in now really doesn't do anything. Nitrates just don't magically show up. They're the end result of the bacteria converting ammonia to nitrites, then nitrites to nitrates. Without really understanding when you saw the spikes with respect to when you yanked your biowheel, I'd say the safest thing to do is to put the biowheel back on and keep it there. Add an ammonia source like you did before (raw cocktail shrimp or fish food) and test every other day or so for ammonia/nitrites/nitrates. If you start seeing nitrates without an increase in ammonia or nitrites, you've got the bacteria you need and are good to go. If instead you start seeing ammonia, then you'll have to redo your cycle.

Roka's idea of seeding your biowheel in your main tank is good - but it assumes you have a viable bacteria population in your main tank. The fact that it's been empty with no ammonia source for 4 weeks makes me think that there's not much bacteria in there to start with to seed anything with.

[roka64]

Kurt has some great points. You definitely want to keep an ammonia source for the bacteria to stay alive. I would say, if you have nitrAtes present and no ammonia or nitrItes in your main, you are good to go and can seed the biowheel in the main.

[Kurt_Nelson]

Originally Posted by roka64

... I would say, if you have nitrAtes present and no ammonia or nitrItes in your main, you are good to go and can seed the biowheel in the main.

I can think of a case where that wouldn't be true.

You cycle the main tank, see the ammonia and nitrite spike and then go to 0.0 ppm, and finish with some level of nitrates... let's say 10 ppm. You now let your tank go 4 weeks without adding anything to create ammonia, and you don't do any water changes. Your water parameters now should be the same as when you left it, 4 weeks ago - 0 ammonia/nitrite and 10 nitrate. That doesn't mean you have any bacteria left though.

[roka64]

Hmmm, that's an interesting point. I have a tank that has been running for a few months (was going to be a QT, just haven't had any new fish come in lately), so I will test that water parameters tonight. Now that I think about it, you probably are correct since that tank has algae growing in it....