A couple of questions about fishless cycling

[Jeremy S]

I am doing a fishless cycling on my new 58-gallon tank and both the nitrites (25+ ppm) and the nitrates (50+ ppm) are off the chart. The ammonia is probably high since I am adding it to keep the bacteria alive. Obviously the tank has finished cycling but do you think one 50% water change will bring down the nitrate, nitrite and ammonia levels so that the fish will be able to stand it? I will not be able to get the fish for about a week so should I just keep adding ammonia and then do a water change the morning before I get the fish? Or should I do a water change now? Thanks.

[anonapersona]

With nitrites above zero you are not finished cycleing yet.

[stoopid]

And to add a little more, the fact the nitrites are only half the nitrates is a good sign that you're over the hump and close to being cycled.

Assuming the nitrites are at zero in a week, as anon explained, you should be able to get the fish (and I'm going to guess that in a week it will probably have finished).

[JSchmidt]

If you still have nitrites registering, your cycle is not finished. 25 ppm is a very high level of nitrites -- I'm a bit surprised a hobby test would even make a distinction between levels above 5 or 10 ppm.

To what level are you dosing with ammonia daily? At this point, you should be adding enough ammonia to take the tank to only 3-5 ppm, no more. If, after dosing the tank to 3-5 ppm ammonia, you register zero ammonia and zero nitrites 24 hours later, your tank is cycled. If you still register either ammonia or nitrites 24 hours later, you're not quite done.

I would do at least a 50% water change, dose to 5 ppm ammonia, then see what things look like in 24 hours.

HTH,
Jim

[stoopid]

Originally posted by JSchmidt
At this point, you should be adding enough ammonia to take the tank to only 3-5 ppm, no more. If, after dosing the tank to 3-5 ppm ammonia, you register zero ammonia and zero nitrites 24 hours later, your tank is cycled. If you still register either ammonia or nitrites 24 hours later, you're not quite done.

That's a really good point... but one question -- assuming he IS adding a lot of ammonia, wouldn't this just take a little longer to cycle but create a ton of bateria so the tank is "uber" ready for lots of fish?

[RClarkofNC]

Maybe, but even if it did, those surplus bacteria would die off once the ammonia doses were stopped and the fish were added since there wouldn't be enough ammonia and nitrite food to sustain them. No harm done, but unnecessarily lengthens the cycling time.

[Dahlia]

It does get your tank ready for a lot of fish.

When I did mine, I did a 100% water change when I finished (of course I ended up deciding to only add one betta because I was too paranoid to trust it had really worked - the betta is quite healthy). You get such high nitrates adding all that excessive ammonia that it seems like a good idea to change all the water out when no fish are in it yet anyway.

[JSchmidt]

Originally posted by stoopid


That's a really good point... but one question -- assuming he IS adding a lot of ammonia, wouldn't this just take a little longer to cycle but create a ton of bateria so the tank is "uber" ready for lots of fish?

Yes, you could cycle a tank so that it could handle some astronomical concentration of ammonia. (There no doubt is some upper bounds, but you could go pretty high, I'd wager.) I've never seen a need for a tank to handle more than 5 ppm ammonia, though, even if it was immediately stocked with a heavy complement of cichlids. I think after a certain point, you'd just be growing a colony of bacteria that will ultimately experience some die-off due to lack of food after you add fish.

I don't know that anyone has ever systematically looked at what amount of ammonia is processed by a tank's biofilter in a set period of time. It would be interesting to see. In the meantime, I've never seen anyone (I don't think) who cycled their tank to handle 5 ppm ammonia in 24 hours that had a subsequent ammonia spike when fish were added.

Also, unless one was certain the cycle was nearly ended, I wouldn't do a 100% water change. The foundering nitrite-eaters will be without food for while, which won't really help them much. I would do a 100% water change AFTER demonstrating the cycle has completed though; I do that regularly.

Jim

[anonapersona]

If one doses too much ammonia, it can create a neverending cycle! I can't quite recall how, but something prevents the final bacteria levels from getting established. I'd have to search to find the details, it isn't very common but I've read about it. Maybe it has to do with the pH level, you do have towatch the pH level as if it gets low, below 6 I think, you get stuck in an endless cycle also. Unfortunatly, I don't know if this is two issues ammonia level and pH, or just one with the pH. I think both are factors.

I would think that setting up a massive bacteria population is not such a great idea. When you stop the ammonia to add the fish and the ammonia level is so low, the bacteria will die off in great numbers. As they do, they generate ammonia, but with so many dead, will there be enough to handle that load or will ammonia spike? It would be so ironic, to have gone through all that trouble and have an ammonia spike anyhow!

[JSchmidt]

I doubt bacteria die-off would cause much (if any) of an ammonia spike. The decline in numbers of bacteria would be gradual, I'd think, and the bacteria don't really make up a substantial volume of the biomass. I have a hard time imagining bacterial die-off being much of a problem.

I do think that very high ammonia levels may retard growth of the nitrite-eaters; there's some anecdotal evidence from lots of folks that supports that phenomenon. I don't think you're likely to see any inhibition if the tank is seeded with ammonia in the sub-10 ppm ranges, though, and especially not in the sub-5 ppm range.

Jim

[anonapersona]

If you go read Dr. Chris Cow's original writeups on this idea, and the second version as well, there is a real difference in the volume of ammonia used.

The first version Fishless Cycling - Chris Cow (http://www.aaquaria.com/aquasource/cycling.shtml) says
"Then simply add 4-5 drops of ammonia per 10 gallons per day until you get a nitrite spike. Once you have nitrites, cut the ammonia back to 2-3 drops per 10 gallons per day until the nitrites disappear. When you get a 0 ppm nitrites reading, you have a fully cycled tank." (This was using lab grade ammonia 4 to 8 times as strong as household ammonia.)

the second version Fishless Cycling revisited -- Chris Cow (http://www.aaquaria.com/aquasource/cycle2.shtml) says
"Add ammonia to the tank initially to obtain a reading on your ammonia kit of ~5 ppm. Record the amount of ammonia that this took, then add that amount daily until the nitrite spikes. Once the nitrite is visible, cut back the daily dose of ammonia to ½ the original volume. One advantage of this method is that the ammonia spike occurs immediately... when adding 4-5 drops/10 gal/day, it could take 4-5 days before the ammonia reaches the same levels. "

It seems to me that the maintainence level of ammonia is much higher in the second version.

And I seem to see a lot of people who are dosing to 5ppm through the entire process, not taking the # of ml that gave 5 ppm as a daily addition and cutting that in half when the nitrite peaks and begins to decline.

[anonapersona]

When I moved the filter from the sick goldfish tank to the new tropical fish tank, I decided I should sterilize the filter with bleach.

I soaked it and lightly rubbed it somewhat clean and rinsed again and again with dechlor, really strong. It smelled fine, so I put it on the new tank. Added 3 small tetra and a small catfish.

On the second day the ammonia was off the chart, I changed 30% water, tested off the chart still, changed 50% water, still off the chart, changed darn near all the water in the tank, maybe 85%, and got a reading of 3 ppm ammonia. I back calculated that it was probably at 15ppm at the peak!

The dying bacteria were throwing off massive amounts of ammonia, the 3 tiny tetras and one small cory in a 10 gallon tank couldn't have done that in a day or 2 but the bare bottom goldfish tank has built up quite a load of bacteria in the filter.

I had to test and change water daily to keep the ammonia on the charts, the nitrite cycle was worse with twice daily changes. Eventually a water change that was way off on temperature killed the tetras, poor things. The cory lived and is OK but barbel-less to this day.

So, anyhow, I am not convinced that the filter bacteria dying off is not a problem.

[Jeremy S]

Originally posted by anonapersona
With nitrites above zero you are not finished cycleing yet.

It’s been such along time since I cycled my other tank that I forgot that you need to have the nitrite at 0 before the cycling is done. :o :o




Originally posted by anonapersona

the second version Fishless Cycling revisited -- Chris Cow (http://www.aaquaria.com/aquasource/cycle2.shtml) says
"Add ammonia to the tank initially to obtain a reading on your ammonia kit of ~5 ppm. Record the amount of ammonia that this took, then add that amount daily until the nitrite spikes. Once the nitrite is visible, cut back the daily dose of ammonia to ½ the original volume. One advantage of this method is that the ammonia spike occurs immediately... when adding 4-5 drops/10 gal/day, it could take 4-5 days before the ammonia reaches the same levels. "

This is the version of fishless cycling that I am using. I haven’t tested the water for ammonia since the first day. Do you think I could be adding too much ammonia? Should I cut down on the dosage? I don’t want to put the tank into an endless cycle.

I still probably won’t be able to get the fish for a couple of days after the cycle is done. Do you think I should do a water change right after the tank is done cycling or should I wait until right before I get the fish?

[RTR]

Chris updated beyond the second article (not at Tom's Place):

http://www.tropicalfishcentre.co.uk/Fishlesscycle.htm

In that one he does add warnings about pH issues with high dosage. The problems of endless cycle occur because the nitrification process eats buffering (KH) and the pH drops to levels below good ranges for the bacteria, so they cease growth or even die.

Chris' first article was based on lab ammonia which is much stronger than household ammonia. The doses are comparable between the two if you allow for the differences in strength of various ammonia products. That is the main reason for the titer basis of judgement rather than the volume dosing.

Don't confuse the nitrification bacteria with the total bacterial presence in a tank. The water and every surface in the tank, even if bare, are heavily coated or suspended with living organisms. The nitrification bacteria are a tiny percentage of the total biomass of bacteria - they are just the ones we worry most about. When you burn out all (or actually almost all) active bacteria, that is many times the mass of the nitrogen oxidizers.

[anonapersona]

Originally posted by RTR
When you burn out all (or actually almost all) active bacteria, that is many times the mass of the nitrogen oxidizers. [/B]

So the huge ammonia spike I saw from nuking the used filter shouldn't happen just from having a large die off of nitrification bacteria? OK, good to know that.

[Jeremy S]

It took 20 ml of Kroger brand ammonia to get water in my tank up to 5 ppm. Ever since the nitrite spiked I have been adding around 10 ml of ammonia per day. After its done cycling should I keep adding 10 ml of ammonia per day to keep the bacteria alive until I add the fish and then do a water change right before I get the fish to bring down the ammonia to safe levels? Or should I cut down on the ammonia to about 3 drops per 10 gallons per day? Thanks.

[famman]

I would continue to add 10 ml like you have been. One good way to test your cycle is to do a massive water change say 90-100%, dose your ammonia and test ammo/nitrite/nitrate the following morning. If you get 0/0/acceptable you could add your fish immediately. If you get any#>0/any#>0/any#, your cycle is not complete.
good luck
:)