Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
1. Had minimum-to zero readings across the board for Nitrogen cycle. (edit: for 4 weeks)
Ammonia: Nitrite: Nitrate: All zeros? But you should be adding ammonia.
2. Tried adding difference sources of ammonia, and used some cycled media. Still nothing.
What different sources? Protein like shrimp or prawn? Fish food? Ammonia from a bottle?
3. Current fish: 6 Platies
Well, no more adding ammonia!
4. Current plants: Ambulia, Hygro, Amazon Frogbit, Bacopa, Java Moss - all are surviving or growing.
Any floating plants can remove nitrogen (in any form) pretty fast. I wonder if the Frogbit and fast growing Hygro are removing enough ammonia that the cycle is complete?
5. Water stained by tannins, I'm guessing from the soil? One peice of manzanite wood but my manzanite usually doesn't leach.
I do not think tannins interfere with the growth of nitrifying bacteria. My Manzanita also does not seem to leach significant tannins. Probably coming from the soil.
6. Filtration is a powerhead powered sponge filter, 40g tank (want to breed Threadfin Rainbows, people have had more success with this type of filtration than others).
What size powerhead?
7. Using Prime.
8. 5g water changes starting yesterday, 3x weekly from now on to remove tannins.
9. pH 7.0, kH 5.0, gH
The nitrifying bacteria thrive under these conditions:
High oxygen (so good water movement)
Ammonia under 5 ppm (So add ammonia to 5 ppm only the first day or so, then allow it to drop to 3 ppm)
Nitrite under 5 ppm (So, if it ever shows up, keep it under 5 ppm with water changes)
KH- These bacteria need the carbon from carbonates, so I would make sure the KH is over 3 German degrees of hardness.
pH- I know these bacteria were first grown in the lab with alkaline water, but I do not know if that is because they need the carbonates, or if they really need high pH.
Some organic acids have some antibacterial properties. Not a lot, and I have not heard of them stalling a cycle.
Moderate temperature- The bacteria grow faster with higher temperature, but water holds less oxygen at higher temperature. Anywhere in the 70s is probably great, higher only if you can assure good oxygen supply. Since most aquarium plants struggle when the temperature gets into the 80s, and you have added cool water fish, I would keep the temperature about 75*F.
No toxins such as fish meds, soaps, surfactants, perfumes (Read the label on the ammonia. Should be pure ammonia, nothing else).
How did you prepare the soil? Did you mineralize it? Or just take it straight out of the garden? Natural soil, where weeds and worms and so on have been living is very good, it even has some of the nitrifying bacteria in it.
What happens when you add ammonia to test 5 ppm? Does it go away really fast? Maybe the plants are using it.