Fish-less Cycling Question

[Piscator]

When one is doing a fish-less cycle with added ammonia, is it necessary to keep the tank covered? I ask this because it seems to me that if there is nothing covering the tank a small portion of the ammonia that is added would evaporate. Wouldn't this, over time, give one the false impression that there is a nice vigorous colony of bacteria growing in the filter media? Or... am I missing something here?

 

[Bignose]

I think that the rate of evaporation is rather small. Ammonia smells pretty strong, so when you smell what you think is a lot, it's actually not a large large amount in terms of number of molecules.

But, if you are really worried, then go ahead an cover the tank. But, I don't think that the tiny percent of ammonia that may evaporate will add up to a lot anyway. Besides, at the end of the cycle, the ammonia will be consumed by the bacteria in a matter of a few hours, so there won't even be time for significant evaporation to occur.

 

[Piscator]

Thanks for the reply!

To help get things started I squeezed some of the bacteria from an established tank filter media into the ammonia laced tank (10 galls) in the evening. The reading was at 8.0 ppm. The next morning the ammonia reading was 1.0 ppm. I added more ammonia back up to 8.0 ppm, and in 12 hours got the same lower result.

This sure seems fast to me. Am I doing this right?

 

[rdd1952]

The biggest issue with not covering the tank is actually the evaporation of water. The more openings in the tank cover, the more evaporation you will have just on a normal running aquarium. Since you have the temperature turned up high during a fishless cycle, you experience quite a large amount of evaporation of water anyway. Leaving the tank uncovered would make that even worse. Besides that, leaving the tank open also allows for lots of dust and other things from the air to enter the tank.

As for the results you have seen, it does seem extremely fast for simply squeezing the old filter into the tank. Usually, that has very little effect on the process. What are your readings for nitrite and nitrate?

 

[Piscator]

As for the results you have seen, it does seem extremely fast for simply squeezing the old filter into the tank. Usually, that has very little effect on the process. What are your readings for nitrite and nitrate?

Readings for both are zero. This is understandable because I only started the fish-less cycle two days ago. I have taken two readings for ammonia today - once in the morning and then in the evening. Both were at 1.0 ppm which is down from 7.0 ppm when I added more ammonia last night. I am going to just leave the tank alone for a few days and see what happens as I take readings twice a day.

 

[K.J.]

My tank had absolutely no hood when it cycled, and it cycled in about a week (all inhabitants are still alive, and once I put them in I never had an ammonia reading.)
I don't think it matters, but it might be hard to keep the water level up. I have to top off said tank 2-3 times a week.

 

[rdd1952]

Readings for both are zero. This is understandable because I only started the fish-less cycle two days ago. I have taken two readings for ammonia today - once in the morning and then in the evening. Both were at 1.0 ppm which is down from 7.0 ppm when I added more ammonia last night. I am going to just leave the tank alone for a few days and see what happens as I take readings twice a day.

Even though you just started the process, since your ammonia has dropped from 7 to 1, you should have a nitrite reading. The only way you wouldn't is if used seed media from and established tank and it is able to handle the nitite as it is produced (not likely as you would then have nitrate), your tank is heavily planted and the plants are using the ammonia rather than it being processed or you have some type media in your filter that is absorbing the ammonia and pulling it from the water. There may be more but those are the ones that come to mind.

Are you running carbon or some type media in the filter that would remove ammonia (nitro-zorb, zeolite, etc.). If so, you should remove it as the tank will not cycle as the ammonia is being removed mechanically rather than by the bacteria. Carbon doesn't specifically remove ammonia but it will absorb it until it is saturated (could be in as little as a day). Most members here only use carbon after medication to remove the last trace elements of the meds (some don't even use it then and just let subsequent water changes remove or dilute them). There are better forms of media for bacteri colonization than carbon. It also has to be changed too often (if you want the absorption qualities of it) since it can become fully saturated in as littl as a day ad at most acouple of weeks). And the problem with changing it is that since the majority of the bacteria colonize the filter media, you throw away a large protion of your bacteria every time you change carbon.

Just keep checking. Don't let the ammonia stay at zero for more than a day or any bacteria you have developed will then die off and you will be back to square one.

 

[Piscator]

Are you running carbon or some type media in the filter that would remove ammonia (nitro-zorb, zeolite, etc.). If so, you should remove it as the tank will not cycle as the ammonia is being removed mechanically rather than by the bacteria.

There are no plants or gravel or rocks - just the water in the tank (10 gallons). I just took another reading this morning and got these results:

Ammonia = 0.75 ppm
Nitrites = 0.0 ppm
Nitrates = 0.0 ppm
pH = 7.2
Temp = 71 degrees

There is no carbon in the filter, just the generic white filter media. Oh, and the water has a slight milky white tint. Is this normal?

 

[rdd1952]

You sometimes get cloudy water as a bacterial bloom. But I don't think your tank is cycling since you don't have any nitrite or nitrate. I didn't think evaporation of ammonia would be a problem but I am beginning to wonder. Obviously, the ammonia is going somewhere and it doesn't appear as though it is being processed by bacteria since there is no nitrite and nitrate.

Since you are doing a fishless cycle, I would first raise the temp. At 71, it will take quite a while for the bacteria to develop anyway. Optimal is in the upper 80s to low 90s. My suggestion would be to add enough ammonia to raise the level back up to about 4 or 5 ppm and see what happens. You may end up having to cover the tank as I guess it is possible that the ammonia is evaporating although I don't think that is the case. Have you had to top the water off during the process? Obviously, adding clean, ammonia-free water would reduce the ammonia reading a small amount.

 

[Piscator]

Have you had to top the water off during the process? Obviously, adding clean, ammonia-free water would reduce the ammonia reading a small amount.

I have not added any new water yet. Oh, and I checked the ammonia this evening and it is still at 0.75 ppm since I checked it 12 hours ago.

QUESTION - When the ammonia level goes down, no matter how slowly, does one immediatly see a reading of Nitrites during a water test? Or does it still take a while for them to show up?

 

[rdd1952]

Yes. Nitrite is the end product of the ammonia being processed by the bacteria. I'm not certain is the transformation is 1 to 1 or not (i.e. 4 ppm of ammonia will yield 4 ppm nitrite) but it should be close. So since you started with 7 ppm of ammonia, you have roughly 6 ppm of nitrite now.

 

[Piscator]

Yes. Nitrite is the end product of the ammonia being processed by the bacteria. I'm not certain is the transformation is 1 to 1 or not (i.e. 4 ppm of ammonia will yield 4 ppm nitrite) but it should be close. So since you started with 7 ppm of ammonia, you have roughly 6 ppm of nitrite now.

Hmmmm Well, then it's rather odd that my API test kit does not indicate any nitrites.

Here's the really odd thing - I have a second 10 gallon tank with gravel and two Zebra Danios in it. They have been in there for three weeks, and I still have no nitrites showing up. The water test results (taken twice a week) over the three weeks are pretty much this:

Ammonia = 0.75 - 1.00 ppm
Nitrites = 0.00 ppm
Nitrates = 0.00 ppm
pH = 7.4 - 7.6
Temp = 79 f - 81 f

I have been doing a 20% water change every week. There is no charcoal in the external filter, and the fish are fed flakes twice a day. The water is crystal clear, and no algae is showing up. Oh, and the tap water is soft and neutral pH.

There has to be "something" I'm doing wrong here???

 

[rdd1952]

The reason you don't have any nitrite reading in the tank with the danios is probably because none of the ammonia has been processed. The danios won't produce a huge amount of ammonia although 2 feedings a day should result in some left over food that decays and produces ammonia. I'm just not sure why you're not seeing any nitrite. I would suggest that you do ater changes more often (daily if necessary) in order to keep the ammonia below .25 ppm. Although danios are very hardy, the level you have will still cause permenant damage to them.