Cycling Netlea tank

I posted this at GTAA, thought I'd post it in my blog for my own future reference.


I am not famous for my patience, but cycling a tank isn't something I would skip on. I posted around 2 months ago about the three 20GL tanks I set up around the same time with different substrates. I learned a lot from that experiment.

Now, I want to share something about cycling a tank with Netlea (or anything similar). Before I start, I want to refer to some basics, read them if you're not sure how/why to cycle a tank.

Wikipedia's short description on Nitrifying bacteria

So, basically you want to make sure your tank has enough ammonia-oxidizing bacteria (AOB) to handle the ammonia produced by your shrimps and convert them to nitrite, and have enough nitrite-oxidizing bacteria (NOB) to convert the nitrite to nitrate.

The end result of a cycled tank is that you have enough AOB + NOB so ammonia and nitrite never will appear in your tank in dangerous concentration.

So

Ammonia (from shrimp) turns into Nitrite by AOB
Nitrite (from above process) turns into Nitrate by NOB
(How to get rid of Nitrate is not discussed in this post, maybe later)

Okay, that's basics and most of us already are very familiar with, and we have discussed a lot of things about how to do it fishlessly, either with rotting fish food, raw shrimp, or pure ammonia.

What else can help the establishment of AOB and NOB? (i.e. speed up the cycling process) These bacterias are known to spawn slower than others because they can't utilize organic food source, very unique in their own right, but the following help,
- Higher temperature (most bacterias grows faster in higher temperature)
- Higher PH (7.8+ is better)
- Higher oxygen concentration
- And of course, proper amount of food source (i.e. ammonia, but not too much, 4 to 5 ppm is about the highest, anything more actually kills these bacteria).

Okay, it's already been a long post but I haven't even touched my main topic. In my new Netlea tank set up 2 months ago, I had a big issue with the cycling process -- the PH is just way too low... it was about 5.3 when new and then gradually goes up to 5.7/5.8 after a few weeks and a few big WCs. In that kind of PH, AOB just can't establish. The reason is one, they don't like acidic water, two, at PH lower than 6.4 almost all ammonia turns into ammonum which these AOB is not very efficient in using. In my first 6 weeks of cycling, I have only tested NO2 once in low concentration. It's entirely possible that the tank was ready after that point since ammonia isn't likely to be present in that kind of PH but I took it more as an experiment than getting the tank ready for shrimp. After 2 months, there's no change, there just isn't any NO2 detected and very low NO3. I actually would put shrimp in there because from others' experience it should be safe, but I wanted to see how long it will be before I see the common signs of a cycled tank.

Anyway, about a week ago, I moved the tank to my basement and moved the Netlea from the 1x 20GL to 2x 16G (the floor areas are about equal). After a day with new tap water, the PH stayed up. One was 6.9 the other was 7.1. What the heck?! I thought by moving them to different tanks I destroyed them. I then thought maybe it's because I was using UGF in the 20GL but not in the 2 x 16G. So I bought a small double layer UGF from AI and put it in one of the two tanks. Guess what? PH dropped from 6.8 to 6.2 in 2 hours. Then it struck me -- I disconnected the UGF, then did some WC to get the PH back to near 7, turn on the heat, and started cycling. I think this should help and this will be the way I cycle these high PH lowering substrate from now on. I will connect the UGF to bring down PH to what I want after the tank is cycled.

Sorry for the long post, just something I learned the past week and may not be of any value. Hope I didn't waste your time.