Ammonia - 3ppm Or 5ppm

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yabadaba

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Hi guys, I'm in the process of fishless cycling two tanks and have based my methodology on the 'Fishless Cycling' guide in the 'Beginners Resource Center'. Based on that I have been topping up my ammonia to 3ppm every time it is processed back to zero, but have seen references since, in other threads, where the aim seems to be to clear 5ppm of ammonia in 12hrs. So, should I be re-dosing to 5ppm instead of 3ppm?
 
Hi guys, I'm in the process of fishless cycling two tanks and have based my methodology on the 'Fishless Cycling' guide in the 'Beginners Resource Center'. Based on that I have been topping up my ammonia to 3ppm every time it is processed back to zero, but have seen references since, in other threads, where the aim seems to be to clear 5ppm of ammonia in 12hrs. So, should I be re-dosing to 5ppm instead of 3ppm?

Most recommend 5 yes. At your stage in fishless cycling it probably doesn't matter since you don't have that much of the ammonia bacteria yet, but if you go up to 5 ppm that will give you a lot more leeway when you stock your tank with your fish.
 
Agree! The ammonia dosing: 2ppm, 3ppm, 4ppm, 5ppm.. really doesn't matter until the final couple of weeks of cycling way off in the third phase, which may be more than a month away! Its in those final couple of weeks that you want to try to get the dosing amount up to 5ppm (without going too much over!) and to watch the bacteria clear both the ammonia and nitrite down to zero ppm within 12 hours or less, for a whole week or so, to prove that the biofilter is ready for fish.

So for most of the long weeks of fishless cycling, the important thing is just to establish one particular "hour" (out of the 24 hours of a day) which will always be your "add-hour" so to speak (this is rough.. we're not talking precision here, just overall sort of thing.) And the rule is that if the bacteria managed to clear all the ammonia down to zero ppm any time during the previous 24 hour period, then you add a new dose of ammonia at your "add-hour." The amount is not so important (2,3,4,5).. its the "pulsing" effect, the A-Bacs seeing a "pulse" of ammonia, then eating it all, then the N-Bacs seeing a "pulse" of nitrite(NO2), then them eating it all and then both species seeing a zero period prior to getting fed again. This is what I have a hunch may be important. There is active interest in this in the waste water treatment plant scientific literature lately.

And of course, you want your "bacterial soup" recipe to be good! The temp should be 84F/29C, the pH of 8.0 to 8.4 is optimal but anywhere from pH 6.3 up to pH 9 or somewhere will grow the bacteria, just at slower speeds as you move off of the optimal 8 to 8.4. And the bacteria need some tiny amounts of calcium and iron but usually your tap water will more than supply enough of that.

~~waterdrop~~
 
Wow....I never realised just how complex/involved this whole biofilter thing is! I actually find it very interesting and it's certainly good to be learning something new virtually every day, but I'll be happy when all this cycling is finally complete and I can divert some attention away from micro-biology and towards choosing fish :). Thanks for the info on the optimum temperature - I did have it at 28°C, so I'll raise that to 29 and hope it speeds things up.

Bu the way, I set up my son's tank (2ft) a couple of weeks after mine, but it actually looks like it might be cycling quicker....probably a result of me having added quite a large amount of mature media from my mature tank into his new filter. The initial dose of ammonia had been cleared by day 8 and the nitrite levels have never 'skyrocketed', unlike in my own cycling 5ft tank. In fact, the nitrite actually drops to zero each time the point is reached where an ammonia re-dose is required. But, the ammonia/nitrite still isn't being cleared within 12 hours, so still a while to go.

Mainly in an effort to rid my tank of a brown algae/diatom 'attack' I did a 33% water change yesterday after giving all the surfaces a good scrub. Straight after that the nitrite measured 0.25, whereas it's usually off the scale, but I expected that to build back up overnight, as the newly added ammonia was processed. Strangely, it still read 0.25 when I checked it earlier today, yet all the ammonia had been processed. So, just when i think I've got to grips with how this works (nitrite is a by-product of ammonia being consumed) I get confused again!
 
Okay, I've just tested the water in my cycling tank again...that's 10.5 hrs after adding 3ppm of ammonia. The ammonia reads zero and the nitrite is somewhere between zero and 0.25. So that's the quickest the ammonia has cleared to date and the lowest the nitrite has been since it first appeared.

Now, from what waterdrop was saying, I shouldn't be re-dosing with ammonia just yet, as that should be done only once every 24hrs?
 
Okay, I've just tested the water in my cycling tank again...that's 10.5 hrs after adding 3ppm of ammonia. The ammonia reads zero and the nitrite is somewhere between zero and 0.25. So that's the quickest the ammonia has cleared to date and the lowest the nitrite has been since it first appeared.

Now, from what waterdrop was saying, I shouldn't be re-dosing with ammonia just yet, as that should be done only once every 24hrs?

You can re-dose whenever you like, but no more than 24 hours, the bacteria needs its food. In this thread http://www.fishforums.net/index.php?showtopic=113861 it's recommended 5 ppm every 12 hours, once your tank can clear the ammonia and nitrite from a 5ppm dose in 12 hours you are good to go.
 
You should only dose once a day. There is really no reason to dose more often since no reasonable number of fish could possibly produce even that much ammonia in a day.
 
also you should do partial water change of 30-40% in an alternate day until it gets stable...
 
Okay, with my 5ft tank I reached the stage where both ammonia and nitrite were clearing within (close to) 12hrs from 3ppm doses. So at the beginning of the week I started raising the ammonia level to 5ppm instead. Now I'm finding the nitrite is clear after about 12-14hrs, but the ammonia is still reading about 1ppm. If I test after say 16hrs it is back to zero.

Are these results sufficient to now do a big water change and add fish, or do I need to persist until ammonia and nitrite are both fully cleared with the the 5ppm dose, within 12hrs? Basically, I seem close to that (and 3ppm does clear), so wondering whether an initial lower stocking level (say my 1 RTBS, 2 x Clown Loaches & 2 Bolivian Rams) would be fine to go with?
 
I would give it just a few more days. The bacteria can theoretically double numbers in 24 hours but nothing really moves that fast. In a few days you should have the added 30% of bacteria need to clear the ammonia that much faster and will know it is safe.
 
Well, just as i thought I was getting there.....

Nitrite is showing as zero, but ammonia processing now seems to have come to almost a grinding halt. It read 1ppm yesterday morning and this morning it's only down to 0.5ppm, where previously it was clearing reliably back down to zero (from 5ppm) in around 16hrs.

I seem to remember that pH can be an issue so I've just tested for that and it's registering as 6.0, where previously it was around 7.6. Is this where the problem lies? I'm guessing I need to do a water change?

Thanks for any advice.

EDIT: Just spotted Sc0tt8's post from yesterday. The answer looks like it's there - big water change and then add some baking soda. Can't believe I didn't spot that before posting!
 
Do a large, near 100% water change to reset the pH. At 6.0, the cycle will stall.
I just drained and replaced about 240 litres, which is approx a 50% change. That took ages in itself, even using 3 x80 litre bins and a pump, but fortunately the pH is now reading about 7.6 again. I'm going to re-dose with ammonia now and hope that the pH doesn't fall again so dramatically. The water in my area is pretty hard (about pH 7.8) so I had hoped this wouldn't happen to me. You think I should still try adding some baking soda?
 
There are just too many variables to know for sure but I agree with OM47 that usually just a large water change will be sufficient to get you farther down the fishless cycling road.

Without a KH measurement you don't know how much buffer is in there to resist the downward movement forced by the now more rapid rate of nitrate production. And of course that rate is a variable itself. Another factor though is that its a lot of fresh tap water, a large volume, so a number of tank conditions will have changed due to that and it may be enough to take you on out to the end of the fishless cycle!

~~waterdrop~~
 

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