Fishless cycling end phase

[puffer]

After moving to a new apartment and having the tank dismantled for quite a few months I've finally started it all up again. Decided to try out fishless cycling and must say I'm very pleased with the scientific approach to it. Everyone who is starting their first aquarium should be forced to do it as it really points out how the nitrification cycle works.

My first attempts to find liquid ammonia was a complete failure, it seems the stuff isn't available for sale anywhere anymore. Finally I found out it was possible to use ammonium chloride which is readily available where I live as a candy seasoning

Anyway, after the first week adding ammonia I noticed the first drop i concentration and after two weeks the tank cycles 2 ppm ammonia per day into nitrite. Ever since my nitrite drop test has been showing concentrations from 2 ppm and above. The test itself seems a bit sketchy with such high readings so I decided to dilute one part tank water with ten parts tap water (nitrite free) and got a reading of 0.25 ppm which in my book translates to 2.75 ppm in undiluted tank water. I know this is an estimate as mixing two liquids of different density distorts the tests but it's accurate enough I think.

My question is this. Can I skip dosing ammonium for a day or two without the bacteria dying? What I want is to lower the nitrite so I can see If the tank cycles a desired amount of ammonia to nitrate during a day. What I'm essentially is doing now is building a larger nitrite to nitrate bacteria population then what is needed. I know I could do a massive water change but I'm on a strict water change / fertilization schedule which I don't want to break.

[RTR]

Ammonium chloride was the original material used for the earliest fishless cycling I ever ran, there is no problem there.

The second phase of the bacterial establishment is trickier. In that original fishless cycle I mentioned, the nitrite phase was done first with lab chemicals, then the ammonia phase. That is backward from what happens more naturally.

What is you tank pH? This is not trivial. Nitrification eats bicarbonate, dropping the pH to levels at which both sets are hard to establish. If your pH has dropped, you absolutely must do water partials to restore the natural buffering of the water. Most fishless cycling articles completely ignore this issue, including the one here.

Additionally, if you did an initial innoculation two or more weeks ago, the nitrite- oxidizing bugs may have starved to very low population densities or even died out completely. If your pH and KH are still at tap water levels, you only need to re-inoculate the tank to re-introduce the nitrite-easting bacteria. They should establish readily.

HTH

[Pufferpunk]

Mmmmm... ammonia-flavored candy, YUM!

[RTR]

In acid conditions, it will be pretty much almost entirely the ammonium ion form, not dissolved ammonia gas. I don't believe that has flavor. What is the pH of candy? I have no clue.

It is the ammonium ion form which is useful to the bugs - remember that Prime and other ammonia "neutralizers" (terrible word for what they do) just lock ammonia dissolved gas into the ion form, which the bacteria then eat for energy.

[puffer]

I checked the tests when I got back from work today and lo and behold, nitrite had dropped to 0.5 ppm. pH though had dropped to somewhere just below 6 (my drop test doesn't go any lower but the color is close). Explains why my vallisneria tips had turned yellowish. I had 6.6 a few days ago but didn't think much about it since there is lots of driftwood in the tank and I have peat underneath the sand. Doing a water change now and will probably change somewhere around 75%.

[RTR]

Nitrification eats carbonate/bicarbonate, which is the only workable buffer for nitrification. Do water partials to restore your buffering before the nitrification bugs die off.

[puffer]

I had pH 7 one hour after my water change yesterday and spiked the tank to 2ppm ammonium as usual. Today the tank has cycled it all to nitrate and the pH have dropped to 6.5. Time to do a series of water partials and I should be done, am I right? How long can the tank be without ammonia while waiting to be stocked? I need to buy a couple of days

[Pufferpunk]

You must keep adding ammonia for it to remain cycled. Right before adding fish, do an 80% WC.

[RTR]

+1 to PP's comments!

[puffer]

ok. I skipped it yesterday, hopefully they are still alive. Spiked the tank now and will get fish this weekend if all is well.

[RTR]

The bacteria will not starve that fast. They are not that fragile.