Cycling predicament

[catfishchaos]

Hello every one! I set up a new tank recently and seem to be having trouble getting the tank to cycle. I used ADA aqua soil which releases Ammonia over time and lowers Ph. I also added quite a bit of wood to the tank (tanks for

Centromochlus reticulatus

) but prior to adding the wood I soaked it in the bathtub for 48 hours with scolding water and changed the water every 6-7 hours to get rid of most tannins. My tap water is 5.5 and in the tank its 5.0 (PH). I have been adding food to the tank to start the cycle but I believe the PH is to low and the bacteria that need to grow are can't handle the acidity. Any tips on what to do?

Regards
James

[Jools]

It should just take longer to cycle. I would stop adding food mind you, if the substrate adds ammonia into the system, then that should be enough.

You will need to careful acclimatise fishes that go into that tank unless they're already coming from a low pH set-up.

Jools

[TwoTankAmin]

I have gotten tanks with a pH in the 4s cycled, However, things are different for acid water tanks than they are for the more "normal" parameter tanks. The ammonia bacteria common in most fw tanks have an issue with acid pH because in such water there is no NH3, total ammonia is 100% NH4. The normal tank ammonia oxidizers cannot utilize NH4 and thus cycling with them wont work and if you have them established in their normal pH range and the PH becomes sufficiently acid, they stop working.

Fortunately, there are species/strains of ammonia oxidizers that have specific receptors which allows them to utilize NH4. They do so less efficiently than the bacteria we normally have, but they do so. Interestingly, the nitrospira (the nitrite oxidizers) work in pretty much all pHs and are selected for based on nitrite levels moreso than other parameters.

Then are two considerations in your situation. The first is that NH3 is the toxic form of ammonia and NH4 is relatively safe. This means the typical danger from ammonia does not exist in your tank. Next, most fish from acid waters have a reduced resistance to most harmful bacteria because these bacteria can not survive in acid water. This may also be an issue because when you bring such fish in from the wild (or an acid water tank) they have not been faced with many of the bacterial pathogens which are typical in most tanks. This means keeping the fish safe requires certain precautions in terms of how the tank is set up and what is in it.

My experience has been with wild altum angels. I had an elaborate plan to put them into uncycled 4.2 pH water which was very soft. Then over the next 6 months or so to gradually raise the pH towards about 6.0. Simultaneously, I worked to get filters cycled for that same 6.0 level in a tank soley for that purpose. The plan was the have the filters working at 6.0 by the time the altum tank was raised to that level, then I would just put those filters into the altum tank.

But mother nature fooled me. The altum tank self cycled before the 6 months were ever reached. The most total ammonia i was ever able to test in the tank was in the .25 to .50 ppm range in the first 2 months. I lost no fish and if you know wild altums, they are not exactly the hardiest fish.

In order to keep your tank safe for your fish you need to know how much NH3, if any, is in the water. Doing this requires you use a total ammonia kit such as the API (or similar) and then using an ammonia calculator to give you the answer. You need to know 3 numbers for this: total ammonia, pH and temperature. You can plug this data into an ammonia calculator to get the answer. I use this one (it allows for fw, sw or brackish with a salinity setting, for fw enter 0). You can find it here http://www.hamzasreef.com/Contents/Calc ... mmonia.php

Unless your test kit states it is measuring Ammonia-nitrogen, select NH (NH3 + NH4), do not use the NH-N setting. Put in the other params and click calculate. The number you wan is the NH3 Concentration. As a rule of thumbs numbers under .02 ppm are pretty much safe for anything. I use a red line at .05 ppm to mark the toxic level. Different fish can handle different levels of Nh3 for different lengths of time. For more sensitive species I would be inclined not to want to reach that .05 ppm nor allow such a level to persist for any length of time.

For those with a scientific bent, you can read about nitrification at low pH levels in the following:

High-Rate Nitrification at Low pH in Suspended- and Attached-Biomass Reactor
Sheldon Tarre and Michal Green
Appl. Environ. Microbiol. November 2004 vol. 70 no. 11 6481-6487
http://aem.asm.org/content/70/11/6481.full

Nitrification in a Biofilm at Low pH Values: Role of In Situ Microenvironments and Acid Tolerance
Armin Gieseke, Sheldon Tarre, Michal Green and Dirk de Beer
Appl. Environ. Microbiol. June 2006 vol. 72 no. 6 4283-4292

High nitrification rate at low pH in a fluidized bed reactor with chalk as the biofilm carrier
S. Tarre, M. Beliavski, N. Denekamp, A. Gieseke, D. de Beer and M. Green
Water Science and Technology Vol 49 No 11–12 pp 99–105 © IWA Publishing 2004

There are lots more studies on this topic. Go to Google Scholar and enter "Nitrification at Low pH" (I suggest you date limit to 2000 - 2015).