9 weeks into a fishless cycle.. Not sure why ph is dropping and NO2 disappeared

[painthead]

I think I am at the tail end of a fishless cycle of a ten gallon tank, but I don't understand what's currently happening right now. I am about 8 or 9 weeks in. About 3 weeks ago I did a big 60% water change when the NO2 and NO3 were getting high. I am using Prime (2 drops per gallon).

After the water change I noticed that the tank wasn't getting rid of AMM as fast as before. But I chalked it up to being normal. Then.. I noticed that my AMM was holding still, and that my NO2 had disappeared, but I still had NO3.

• AUGUST 28: AMM (2.0)
• AUGUST 31: AMM (2.0)
• SEPTEMBER 2: AMM (2.0)
• SEPTEMBER 3: Went to the LFS and they gave me a bunch of sponge from one of their tanks. I stuffed it into my HOB filter.
• SEPTEMBER 7: I tested the ph and it was 6.0 (maybe less? the test only goes down to 6). My tap water is 7.2 (ish). So I did a big 60% water change. PH (7.2) / AMM (3) / NO2 (0) / NO3 (0)
• SEPTEMBER 8: PH dropped to 7.0 so I did another big water change. PH (7.4) / AMM (3)
• SEPTEMBER 9: PH is 7.0. AMM is 2. Nitrites are zero.

Is this all seeming normal or did I goof up somewhere? I mean, something is definitely happening in the tanks, right?

 

[painthead]

Just checked my water.

SEPTEMBER 10: PH (6.8); AMM (1); NO2 (0); NO2 (5)

time for a 50% water change?

Edit- just did a 50% water change and the PH is back to 7.3 and loaded the AMM back to 4 ppm; will report back in 24 hours

 

[jchuck]

I think I am at the tail end of a fishless cycle of a ten gallon tank, but I don't understand what's currently happening right now. I am about 8 or 9 weeks in. About 3 weeks ago I did a big 60% water change when the NO2 and NO3 were getting high. I am using Prime (2 drops per gallon).

After the water change I noticed that the tank wasn't getting rid of AMM as fast as before. But I chalked it up to being normal. Then.. I noticed that my AMM was holding still, and that my NO2 had disappeared, but I still had NO3.

• AUGUST 28: AMM (2.0)
• AUGUST 31: AMM (2.0)
• SEPTEMBER 2: AMM (2.0)
• SEPTEMBER 3: Went to the LFS and they gave me a bunch of sponge from one of their tanks. I stuffed it into my HOB filter.
• SEPTEMBER 7: I tested the ph and it was 6.0 (maybe less? the test only goes down to 6). My tap water is 7.2 (ish). So I did a big 60% water change. PH (7.2) / AMM (3) / NO2 (0) / NO3 (0)
• SEPTEMBER 8: PH dropped to 7.0 so I did another big water change. PH (7.4) / AMM (3)
• SEPTEMBER 9: PH is 7.0. AMM is 2. Nitrites are zero.

Is this all seeming normal or did I goof up somewhere? I mean, something is definitely happening in the tanks, right?

The dropping ph is completely normal. The nitrification process—the biochemical process where ammonia is broken down into nitrites naturally produces hydrogen ions (H+), which makes water more acidic, thereby giving you a progressively lower ph reading.

You also likely have soft water coming out of your tap. Eg parts of the Pacific Northwest. Harder water tends to buffer ph better. Meaning there are other hydroxyl (OH-) ions easily available in the water to combine with the hydrogen ions to form water molecules.

If you have soft water you can add crushed coral to buffer your water, which will not only raise the ph, but also help buffer it. Meaning—prevent it from drastic swings in ph when small changes to the acidity happen.

Good luck! Continue to have patience. Good job on doing the fish less cycle.

 

[painthead]

September 11: 24 hours later and PH (6.7) AMM (1.5); NO2 (0); NO3 (10)

I did a 60% water change and boosted the AMM. Current stats are PH (7.2) AMM (4.0)

 

[jchuck]

You most likely have soft water (lacks pH buffering ability.) You could use crushed coral to increase and buffer pH. Do not use any products that chemically increase pH as this is not a sustainable solution over the long run.