Need Advice

[Sheila]

Ok....it's been 6 weeks now since I set the tank up and I'm still having trouble. Catastrophe with too many fish at first and high ammonia & nitrites. Anyway, got that under control and had both to zero. Then 2 weeks ago I added 4 fish and the tank did ok...initially ammonia went up some but nitrites stayed negative, then ammonia came back to zero. This past saturday, I checked ammonia and nitrites and they were both still zero, so I bought 3 fish. On sunday, I checked the tank and my ammonia level was 1.0 and nitrites were 0.3. I did a 25% water change. Yesterday, my ammonia and nitrites were still the exact same, I did another 25% water change. I also took a sample of water to my lfs and had them double check my readings (they were accurate). Today, I checked the water and my ammonia level is maybe 0.75 (hard to tell my scale goes from .25 then to 1.5, but it's lighter in color than it was yesterday). My nitrites tested at 0.8 today. I just don't get it! When will my tank finish cycling and why are my readings going up? The ammonia is coming down, but nitrites are going up. Is this normal? My fish all look and act great and don't seem to be in any distress. I guess these frequent water changes will be in my future for a while? Is there a scale to go by on when to do a water change, as in the highest/lowest ammonia and nitrite level acceptable? I have cut back on feeding to once a day (and then only half the normal amount). Am I doing something wrong, or is this what should be happening?
Sheila

 

[heresmike]

Hi Sheila. Sorry I can't answer all your questions, but some!

Yes, it's normal for nitrites to go up when the ammonia goes down. Then the nitrites should go down and the nitrates go up. Eventually ammo and nitrites should stay at zero. You've already seen that happen, but for some reason those last 3 fish you added caused a mini cycle. Have you been doing any other maintenance, and possibly overcleaning the filter??

I've always cycled w/o fish, but have heard that when using fish and ammo reaches 1.0, you should do a partial water change. Don't know about the nitrite level... maybe someone else does.

I would suggest keep doing the partial water changes when ammo reaches 1.0. Hopefully it stabilizes for you!

 

[pendragon]

Sheila,

Relax. Take a deep breath. Everything is perfectly normal here.

When an aquarium finishes its initial cycle, it has reached an equilibrium point. For your certain amount of bioload, a certain amount of ammonia is produced. The correlative amount of bacteria establishes to consume that much ammonia, and produces a certain quantitiy of nitrite in the process. A particular amount of nitrite-consuming bacteria form (exactly enough to consume the nitrite being generated), and produce a given amount of nitrite as a result. Nature finds the correct balance so that all stages in this process are efficient. The right amount of bacteria form to deal with the amount of "food" it finds - if bacteria kept colonizing, but there was no more initial input into the system (ammonia), some of the bacteria would just starve and die off, leaving you with exactly the amount that can consume the "food" available to it. So...

When your tank cycles, it has exactly the right amount of bacteria for your bioload, so the ammonia isn't measurable. When you add fish, there's suddenly more ammonia (more "food" for the bacteria), so the bacterial colony grows to consume the extra ammonia - this takes a little time, but not nearly as long as it took in the initial cycling. After the new bacteria grows to deal with the elevated ammonia levels, more nitrite is being produced than was previously, and it takes a little while for the nitrite-eating bacteria to catch up. Make sense?

Any time you increase the bioload in your tank a "mini-cycle" will follow. It is inevitable. Ammonia and nitrite levels will rise for a brief while, no matter how established your tank was previously, but the spikes should never be as pronounced or as long as they were during your first cycling in the tank. The bacterial colonies just need a little time to grow sufficiently to cope with the added bioload. This is why even after a tank is cycled, you should never add large bioloads to a tank at once, only over time. If you increase the bioload by too much at once, even the "mini cycle" will produce toxicity spikes large enough to cause you major problems. Similarly, if you ever reduce the bioload in a tank, for whatever reason, the size of the bacterial colonies will shrink proportionally (there is less "food" with a reduced bioload, so some of the bacteria "starves" and dies off).

The point is (didn't think I was getting there, did you? ) that anytime a tank reaches equilibrium, it is for the specific bioload currently in the tank. Change the bioload by adding or removing livestock, and the tank will adjust itself accordingly. It's perfectly natural.

As for water changes...

Ammonia and nitrite are different animals with regard to toxicity. Nitrite is poisonous to fish, but not nearly as much so as ammonia. Many people (including me) don't do water changes due to nitrite unless you really feel it's getting excessive. Unless you have terribly sensitive fish, they can handle a fair amount of nitrite with no ill effects. However, if you feel they're in discomfort and feel compelled to water change, then by all means do so. Go with your gut, but don't walk on pins and needles about it. Just remember, small water changes are better for your fish than large ones. Doing a 15% water change daily is much better than doing a 40% change every other day.

The toxicity of ammonia, which is very important, is terribly dependant on your pH level. At a pH of 6.5 even 10 ppm of ammonia is relatively "safe", but at a pH of 7.8 even 0.5 ppm can be deadly. If you're pH is 7.2-ish or lower, I wouldn't even bat an eyelid at 1 ppm (or 2 or 3 or probably even 4 ppm, for that matter). For more info on the relationship between toxicity of ammonia and pH, check this excellent FAQ. Look at the 'How Much Ammonia Is Too Much?' section. Use the chart there to make an educated guess at what ammonia level is the "danger zone" for your pH value, and just keep it below that. If your pH is high, you should probably consider *gently* bringing it down (unless you have a fish that requires a high pH).

At any rate, I think you're doing just fine. Everything you're seeing is normal. You're just going through a "mini-cycle" adjustment to your change in bioload. It will pass pretty quickly.

Hope that helps. Sorry for the long-windedness!

pendragon!

 

[Dorsal]

Thanks for that excellent post, pendragon. Unfortunately, the link doesn't work

I started fishless cycling my tank 9 days ago. On the 5th day the Amonia level dropped to 0, but on the 4th day the nitrites spiked off the chart. As soon as the amonia levels dropped, I cut the amount of amonia I was putting into the tank in half as is suggested.

Unfortunately it is day 9 now, and the nitrite is still off the chart. Does anyone have any idea about how long it might take the nitrites to begin to reduce? In 4 days I'm scheduled to put fish in. From what I've read here it should be alright with a nice big water change before hand ??

 

[Dorsal]

oops I forgot to add that nitrates started to appear on the 4th day too, and they are now off the scale at 110 too

 

[Sheila]

Pendragon, Thanks for setting me at ease about the tank. I was able to get to the artical you linked and it was quite helpful. According to it, my ammonia level should be at 1.2 to 1.6 before I do a water change. The pH of my local tap water is 7.5, thus my tank is about that as well. I am assuming that you meant not to do partial water changes to bring the ammonia or nitrites down unless they are greater than 1? I know I read in a another post that you don't want to dilute the nitrites too much. I just want to do the right thing. My fishies all look very happy and they all get along great. This mini cycle thing just stresses me out...LOL I am planning on getting maybe 3 o4 4 fish easter weekend. Will that be too soon if my ammonia and nitrites are back to zero by then? Sheila

 

[Sheila]

Just thought I'd give an update that my ammonia level is about 0.5 now and my nitrites are still about 0.8, so with the 25% water change last night, the ammonia level came down slightly and the nitrites stayed the same. Hope this is what I want. Thanks All
Sheila

 

[tstenback]

Dorsal

Depending on the initial ammonia level to cause the spike the nitrite spike could last a couple of weeks or so and the nitrates can be looked after with daily water changes of 15%-20%. The nitrates will always be with you as they are the final product of the biological filter process. the nitrites will drop very quickly when they do come down.

 

[pendragon]

Dorsal,

Unfortunately, the link doesn't work

Drat.

Try this one: http/faq.thekrib.com/begin-cycling.html. You'll just have to manually scroll down to the part about ammonia and pH.

Unfortunately it is day 9 now, and the nitrite is still off the chart. Does anyone have any idea about how long it might take the nitrites to begin to reduce?

Nitrite normally takes longer to drop than ammonia does. IME, about one-and-a-half to two times as long, but that's only a rough guess. In any event, it would be very untypical if your nitrite wasn't still spiked at Day 9. My guess would be you have *at least* a few more days to wait, and even that would be a very fast cycle.

In 4 days I'm scheduled to put fish in.

I'm curious why you would "schedule" the addition of fish. Your cycle will be done in its own timeframe, not ours. Cycles are difficult to predict at best, and impossible at worst, but assuming your tank will be cycled and ready for fish in two weeks is a shaky gamble. If your tank isn't finished cycling by then, IMHO, adding fish to a cycling tank "cold turkey" like that is far worse for the fish than if you had cycled with fish from the beginning. ("Here, fishy, let me take you from a stable environment and dump you suddenly in a tank full of POISONOUS NITRITE!" *insert villainous laughter here*). You also may get another "mini cycle" superimposed over your ongoing one if the new fishes' bioload isn't equal to the quantity of ammonia you've been putting in. Personally, I wouldn't recommend it, but they're your fish. If it were my tank, no fish go in the tank until the cycle is finished. You just can't schedule the completion of a cycle. It would be nice if nature were that predictable, but it isn't.

pendragon!

 

[Dorsal]

Thanks pendragon. The problem is that I am being given the fish by a friend that is coming over to see me on Sunday It's very nice of him to do it. I'm not sure what to do... I'll keep monitoring it... Make a decision on Saturday hey That will have been 9 days for the nitrites, and 4 for the amonia