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.
