Fishless Cycle - Advice Needed

[TwoTankAmin]

change a lot of water- at 16 ppm nitrite is starting to inhibit a cycle and at 32 you are likely killing off bacteria.
 
Part II of those articles is where I have put information on ammonia and nitrite as well as on how to do diluted testing. Its easier for me to send folks to Part II for the diluted testing directions than to have to post them over and over
 
The are both a lot of similarities as well as several major differences between fishless and fish in cycling. The most important considerations, imo, are that fishless never harms any fish or inverts, it lets one stock fully when done which takes a whole lot longer when done fish in. But bear in mind that for a very long time there was no such thing as fishless cycling and tanks were always cycled with fish. The overall process of cycling is the same both ways. Perhaps the biggest benefit of fishless cycling is the use of seed media and/or the use of one of the viable bacterial stater products. It is now even possible to set up a tank and have it be cycled instantly if you have enough of the right things to put into it.

 

[alexpb22]

Thanks TwoTankAmin, I just did about a 90% water change. Nitrites are still really high but only dosed ammonia up till .25 ppm. May leave it for a couple of days without adding ammonia and see if the Nitrites come down. Will then follow your guide and see what happens

 

[alexpb22]

Ok I have done a couple of water changes since I last posted and managed to bring my Nitrite levels down to a much better level for reading. I didn't add any ammonia though as I didn't want them shooting up again and as I have learnt from TwoTankAmin, daily doses aren't needed.

However after my last water change, yesterday morning I tested the Nitrites and they came up as about 0.5 ppm which was great so I thought that I wouldn't dose ammonia until after testing this morning. As I had a good level of Nitrates showing up I was hoping that overnight my Nitrites would drop to zero but I've just tested them and they have stayed exactly the same!

I'm so confused now, I was pretty sure they'd zero out but they haven't. Should I just follow TwoTankAmins cycling instructions or should I leave it another day before dosing up the Ammonia? I'm worried if I do, that they will just go through the roof again

Going by TwoTankAmins cycle guide, I think I should be doing a dose of 3ppm

 

[alexpb22]

Ok I had to go ahead and dose some more Ammonia this morning, so I put in 2ppm just to make sure I didn't do too much. It's 6 hours later and my Ammonia has gone down to 1ppm but my Nitrites have gone up to 4ppm so nearly off the scale again.

I suspect by the morning that they will have gone off the scale completely which is worrying.

Can anyone shed any light on my last post? Thanks for any help

 

[TwoTankAmin]

Yes its simple. Ammonia bacs multipy much faster than the nitrite ones. The the second factor is that they start later.
 
So we add ammonia and wait for this to cause the ammonia bacs to multiply until they process all the ammonia, but this is not an overnight process, it takes some days for it to happen. During these days the ammonia bacs are making nitrite. But the population of nitrite bacs is minimal and multiplying slowly.
 
Now for the math. 1 ppm of ammonia can convert into 2.55 ppm of nitrite. So we add 3 ppm of ammonia and as it drops to 0 it makes a total of as much as 7.65 ppm of nitrite. And this nitrite wont start to drop for many days. In fact, when we add that 2nd dose of ammonia we have now supplied enough material potentially to create 15.3 ppm of nitrite. By the time we have added the 2nd ammonia addition there are way more ammonia bacs than nitrite bacs. As a result ammonia will drop pretty fast but nitrite wont, in fact it will rise. But as the level of nitrite induces the bacteria to reproduce, it will eventually hit a level where it goes "over the hump" and then we will see a fast sharp drop.
 
Now to relate this to the cycling method in the cycling article. The article uses a method designed to prevent a build up of nitrite to a level that stalls or reverses the cycle. It does so in two ways. The first is to control how much and when ammonia gets added. The second is to be sure that before we add more ammonia that we indeed have nitrite. That is the reason for the levels specified for ammonia and nitrite before one supplies the second ammonia addition. If there are 2 ppm or more of nitrite, we know that there is and has been enough nitrite present to have started the nitrite bacs multiplying. Remember that the bacteria reproduce when ammonia or nitrite levels exceed their maintenance needs. Once they are well fed and find there is still more food available, they will reproduce. So by insisting that several ppm of nitrite are present before that next ammonia addition, we know the bacteria are very likely already multiplying. And that initial reproduction will mean that some amount of the nitrite is being turned to nitrate. This should hold down level that nitrite will top out at before it turns down.
 
In simple terms, ammonia should drop handily well before nitrite even peaks. And this is exactly what we normally see and what you are seeing now.
 
From your picture it looks like your reading is near .25 ppm. Its hard to tell as the test tube is not high enough on the card to be next to that color bar. But if your levels are ammonia at .25 ppm or less and nitrite is under 1 ppm, then yes its time to add the ml equivalent of 3 ppm as determined by the ammonia calculator here. This would mean you are nearing the end of the cycle. However, since you have mixed methods things may be less clear.

 

[alexpb22]

Thanks very much for replying TwoTankAmin and that does all make sense and I really appreciate the time you're taking to help me out.

I guess because I had high nitrate levels I was expecting to see the low level of nitrites drop overnight and get converted to nitrates and because they hadn't it kinda threw me.

 

[TwoTankAmin]

I hate nitrate kits. tTey are inaccurate mostly and people put too much weight on the test results. At best they are usable for direction. I personally will never trust hobby kit nitrate test results. Most fw tanks which are given proper maintenance and water changes wont have any problems from nitrates unless one is starting with them too high from one's tap.

 

[alexpb22]

Just thought I'd let you know that I've had my first day of zero Nitrite readings after adding 3ppm the day before. I've dosed it up again and hopefully will get the same result tomorrow and the next day and then I'm on course to actually getting some fish.

So thanks to everyone who has posted and thanks to TwoTankAmin who has advised and who's cycling guide I switched over to following the last few days! Wish I had followed it to start with but I'll know for next time.