Fishless Cycling Help Please

[Flubberlump]

I started my fishless cycle about 3 weeks ago using some mature filter media from my current tank. 3ppm of ammonia has been getting processed to 0ppm in under 12 hours for a couple of weeks, and at the start of this week the nitrite had dropped from off the scale to about 0.2.

I went away on Tuesday afternoon, and dosed the ammonia back up to 3ppm at about 4pm on Tuesday. I got home this morning at 9am and tested the water obviously expecting to find 0 ammonia and 0 nitrite after dosing no ammonia yesterday. Instead, I found 2.4 ammonia and 0 nitrite. I tested the ammonia twice to be sure. I didn't add any more ammonia, and decided to wait a bit to see if it dropped at all.

I've just tested again and it's still the same, so I tested the pH. The tap water is about 8, and the tank water had dropped to 6. I did a 20% water change which brought it back up to 7.5, and dosed the ammonia back up to 3ppm. Is this ok?

Also, the nitrates have been off the chart since the beginning of the cycle. I've just tested them out of interest after the water change and they're reading at about 5. I have two nitrate test kits so used both, and they both had the same result. Is it possible that the nitrates are so high that the tests can't register them?

Thanks in advance.

 

[Flubberlump]

This morning's water parameters: ammonia 2.4, nitrite 0.8, pH 7, temperature 28C.

So it seems the cycle is now going very slowly. It was going quite quickly before. What should I do now? Should I add some bicarb?

 

[Primous]

I don't mean to dampen your spirits considering it took just over 8 weeks for me to cycle. But in essence you're wasting time by toping up your ammonia count to 3ppm. You need to raise the count to 5ppm. When your bacs can deal with that and the resulting nitrite in under 12 hours then you have cycled.

3ppm will leave you open to a lot of problems once you add fish. So since your taking the time to cycle now, you might as well do it right sort of thing. Anything less is just a waste of your time...

 

[Flubberlump]

I've read different things from different people. Some people say to only dose the ammonia back up to 1 or 2ppm to avoid really high nitrite levels which can cause problems in the cycle and encourage the wrong type of bacteria. So I don't know what to do for the best really!

 

[Flubberlump]

Am I right in thinking that high nitrate levels cause the drop in pH? In which case, should I add bicarbonate of soda to increase the pH, or do a large water change to lower the nitrates?

I'm assuming that once the tank is cycled and stocked, and I have done the large water change to lower the nitrates, I shouldn't experience the pH crash because I'd be doing weekly water changes to lower the nitrates? Out of interest, these are the gH and kH of my tank water and tap water:

Tap water gH - 240
Tap water kH - 120

Tank water gH - 320
Tank water kH - 10

Should they change like this? Obviously the tap water has a high buffering capacity, but this has crashed right down now. Anyone know what causes this? And why would the gH increase in the tank? All I have in there is unipac black sand and a piece of rock which I believe is Yamaya rock.

 

[Flubberlump]

Anyone?

 

[pern]

Seems your cycle is coming along. If your ph keeps crashing into the 6's and you get sick of partial water changes to boost it, sure, add some bicarb to get it closer to 8. 2-3ppm should be absolutely fine unless you're planning on adding huge numbers of fish. Getting nitrite to 0 in 12 hours takes a lot longer than the ammonia to 0 in 12 hours. You're getting there : )

 

[Xraymark]

+1
It's fine to add bicarb during a cycle to keep the ph up. Very high nitrates can drop the ph. The reason to drop dose of ammonia is to reduce the load on nitrites going so high as you stated the wrong bacteria can form. Once your nitrites zero you can increase the ammonia to 4-5ppm or keep at 3ppm and stock accordingly.
Ultimately your tank ph will be close to your tap ph. It can change over time but your weekly water change will help keep it consistent.

 

[Flubberlump]

Thanks for the help.

That's what I thought, I wasn't sure whether adding bicarb or doing a large water change now would be better. How long does the bicarb keep the pH up for? If I added bicarb to raise the pH to around 8, like my tap water, would it stay at that level unless the nitrates got even higher?

My current tank has a stable pH of 7.5 - 8, and the tap water has a high KH, so it'll be fine once it's cycled, just wanted to make sure I did the right thing now it's stalled to get the cycle going again.

Before it stalled, it had just got to the point where 3ppm of ammonia was being processed in 12 hours. I just dosed the ammonia up to 4-5 ppm and that's when it stalled due to the pH crash! Typical! Anyway, I'll add the bicarb and hopefully it wont be long now.

Should I just add a teaspoon at a time and test after an hour or so to check the pH? Never done it before.

 

[Xraymark]

Chuck in a tablespoon and check ph in an hour. Yes your ph can drop again with the rise in nitrates but it takes time. Just add more bicarb.

 

[OldMan47]

A kH of only 120 is a bit on the vulnerable side in terms of pH stability. In my tap water it runs closer to 230 ppm. My tap water is quite stable in a tank as long as I do the required water changes, but it is not infinitely stable. At a pH of only 6.0 before a water change, you do not have enough alkalinity to deal with the nitrates you are creating. That does not put you in an impossible situation because you are probably making more nitrates during a fishless cycle than you ever will once your tank is running with fish in it. We intentionally maximize the fishless cycle so that any reasonable stocking will produce less ammonia than we use during the cycle. That means that any reasonable stocking will be within bounds after a fishless cycle is established.

 

[Flubberlump]

Chuck in a tablespoon and check ph in an hour. Yes your ph can drop again with the rise in nitrates but it takes time. Just add more bicarb.

That's what I thought, I doubt it'll get to a level where it'll drop again before the cycle finishes, unless it takes an age to get through the last little bit, but I'll be keeping an eye on it.

 

[Flubberlump]

A kH of only 120 is a bit on the vulnerable side in terms of pH stability. In my tap water it runs closer to 230 ppm. My tap water is quite stable in a tank as long as I do the required water changes, but it is not infinitely stable. At a pH of only 6.0 before a water change, you do not have enough alkalinity to deal with the nitrates you are creating. That does not put you in an impossible situation because you are probably making more nitrates during a fishless cycle than you ever will once your tank is running with fish in it. We intentionally maximize the fishless cycle so that any reasonable stocking will produce less ammonia than we use during the cycle. That means that any reasonable stocking will be within bounds after a fishless cycle is established.

Thanks. The water in my current tank is a stable pH and I do weekly small water changes. Once I've done the large water change at the end of the cycle in the new tank the pH will be 8. I'll be running co2 for heavy planting so it may lower slightly but I don't mind that as it's a bit high anyway. I'd never let the nitrates get high enough to affect the pH and I'll be doing regular water changes anyway as I'll be dosing ferts. It's just the fishless cycle I've never done before as I'd never heard of it until I found TFF. Just want to make sure I do everything correctly.

1 tablespoon of bicarb added! I'll post the progress up here as it may help others too. Should get going again now and it wasn't far away from finished before the stall!

 

[Flubberlump]

1 hour after adding 1 tablespoon of bicarbonate of soda, the pH has risen from 6 to 8. Thanks for your help everybody!

Does anyone know why there's such a difference between the GH and KH of the tap water and tank water? Just curious, I like to know the science behind things so I understand what's happening and why.

 

[Flubberlump]

So, this morning, the ammonia that I dosed yesterday has been processed, but the nitrite hasn't. I've read that it can take a while for the bacteria to start functioning fully again after a stall. Is this the case? If so, how long should that take? It also seems that the nitrite bacteria take longer than the ammonia bacteria to get going again, which would make sense seen as they also take longer to develop and multiply.

Is there anything I can do to speed it up? The temperature is currently at 28C, should I turn it up a bit?