Fishless Cycling

[Egmel]

Hmm, interestingly enough I'm having the same issue as was discussed before, turning the heat down from 30 to 25 caused my tank to re-cycle, thankfully I had no fish in at the time but it does mean that I'm not ready for fish this weekend

Basically a few days ago my tank was able to process 8ppm of ammonia to zero in 12 hours, this was just after the previous talk of how bacteria might be affected by temp so I decided to turn the temp down even though my nitrites weren't being processed, just in case there were going to be any issues. Well there were, over the period of about 48 hours my tank stopped processing ammonia, it was not an instantaneous stop, more of a decline, such that I was left with 4ppm for 24 hours straight. It has just started to drop again now and managed about 2ppm last night.

This to me suggests more than just coincidence and that maybe this should be looked into, are there different bacteria that work at different temps? Should we advise that the cycling be done at a temperature suitable for the fish so that there isn't this thermal shock at the end of the cycle?

I'd be really interested to hear what others have to say about this and whether there have been other instances of this.

 

[rdd1952]

The temperature change is not an issue. If your tank wasn't processing nitrite, it wasn't cycled. In a completely cycled tank, bacteria can survive for 2 or 3 days without food (some will die of but not enough to cause a problem). If your tank is cycled, it should be able to process 4 to 6 ppm of ammonia back to 0 ammonia and 0 nitrite in 10 to 12 hours AND increase the nitrate level (it should be off the chart at the end of the cycle so you may not be ale to tell that it's rising).

If your nitrites aren't rising as the ammonia is cycling through, you have another issue that is preventing your tank from cycling.

 

[Egmel]

The temperature change is not an issue. If your tank wasn't processing nitrite, it wasn't cycled. In a completely cycled tank, bacteria can survive for 2 or 3 days without food (some will die of but not enough to cause a problem). If your tank is cycled, it should be able to process 4 to 6 ppm of ammonia back to 0 ammonia and 0 nitrite in 10 to 12 hours AND increase the nitrate level (it should be off the chart at the end of the cycle so you may not be ale to tell that it's rising).

If your nitrites aren't rising as the ammonia is cycling through, you have another issue that is preventing your tank from cycling.

Sorry I think I wasn't clear, I know it wasn't cycled, I never said it was, what I did say was that my ammonia processing bacteria appeared to die off/become less effective when I dropped the temp from 30 to 25.

I was feeding them and checking the ammonia levels every 12 hours, there was a noticeable slow down after the temperature drop.

I'm still waiting for my NitrItes to drop from off the chart (That annoying greeny blue colour that's too close to the zero colour for my liking in the API kit) to zero and for my NitrAtes to pick up, they're at 5ppm at the moment, they fluctuated a bit when I added my plants but are settled at the moment.

My only issue now is that my PH seems to be all over the place, it starts off relatively high (7.6) jumped higher when I added the ammonia (8.8) and slowly dropped back down (helped when I added some mopani wood) and is now at 6.2.

I have all the data for my cycle, I'd be quite happy to post it if anyone is interested.

 

[rdd1952]

My only issue now is that my PH seems to be all over the place, it starts off relatively high (7.6) jumped higher when I added the ammonia (8.8) and slowly dropped back down (helped when I added some mopani wood) and is now at 6.2.

Don't worry about the pH. It will fluctuate wildly during cycling as the ammonia is present. As for the temperature change, higher temps promote bacteria growth. When you lower the temp back down, it could slow the growth but I doubt that you're actually experiencing a die-off.

 

[Egmel]

When you lower the temp back down, it could slow the growth but I doubt that you're actually experiencing a die-off.

I've had a thought that it could be to do with how fast they process ammonia, a bit like our metabolic rate, the warmer it is the faster they use up the ammonia, which could be why as the temp was reduced they slowed down. Either way they're starting to process it again and it's just a case of playing the waiting game!

 

[scubadoo]

This all interesting stuff Egmel.

As you've noted, I do suspect that the temperature drop off contributed to the problems I experienced in my tank after adding fish. All has been fine for a while now I'm glad to report and the fish seem to be thriving.

To be on the safe side, I would tend to agree that its best to cycle the tank at the temperature that you intend to add the fish. It may take a bit longer for the bacterial colony to establish, but its likely to cause less problems in the long run.

 

[fUbAr]

mine's been cycling for 3 weeks now... and still not seen the Nitrites drop back down

im getting bored of my new hobby because there isnt any fish in there!

 

[Egmel]

mine's been cycling for 3 weeks now... and still not seen the Nitrites drop back down

im getting bored of my new hobby because there isnt any fish in there!

That's exactly what my boyfriend is saying. He's gone to the shops today so I'm just praying he doesn't come back with any fish

 

[blue_soda025]

I've been doing the fishless cycle using the add & wait method for 13 days now. Just bought a nitrate test kit today, so I went and tested the water and it turned out to be 110 ppm?! Ammonia and nitrite levels seem to be normal though, but why are my nitrates so ridiculously high? I have some live plants in there too. Also, I used the Nutrafin test kit for this.

 

[rdd1952]

blue_soda, have your ammonia and nitrite levels gone through the rise and fall yet? If the ammonia is being processed in 12 hours or so then it would make sense that some nitrite is also being processed and producing nitrate. Also, have you tested the nitrate level in your tap water? It could be that the level is already elevated from the tap.

 

[blue_soda025]

Ammonia has spiked. I'm adding some ammonia almost daily now, when it drops to 0.5 - 1.0 ppm to bring it back to ~2.5 ppm. Nitrite is currently >1 ppm (test kit can't read higher than that) and has been for 4 days now. I tested the tap water for nitrates and there were zero, so I'm confused about how it could've rised so quickly.

 

[rdd1952]

It is odd that it has gotten that high so fast. Of course, some nitrate kits, my API kit being one of them, are very hard to read once they get past about 40 ppm. I really can't differentiate the colors past that.

 

[blue_soda025]

In this case, would it be a good idea to do a water change or should I just leave it? I was also thinking of adding more water since the water level has dropped a lot from all that testing and evaporation.

 

[rdd1952]

I wouldn't worry about doing a water change but you may want to top the water off. Just make sure you use dechlorinator.

 

[Lord Zogat]

My fishless cycle is driving me nuts. I am now on week six, It took 5 weeks for the ammonia to drop to 1ppm, but would not go below that. It was recommended I bring it back up to 4 ppm and its stayed there for a week now.

I can't think of anything that would be effecting the process. I add nothing but water dechlorinator to the water in the tank. There are plastic plants, several boiled stones and plastic slate rock.

The only thing I can think of is the plastic acrylic hose that takes water to the filter. I am getting to the point where i am thinking of giving up. Should I replace my filter cartridges?