During the fishless cycle..........

[naiku]

Once the nitrites start to drop (after the spike) do they drop suddenly? I am using an API test kit which goes from a light blue color, to purple. For a few weeks now when I would add in the drops to the water, they would turn purple instantly (as they fell to the bottom of the tube, before I even shook the tube) ............ but the last couple times I have tested, the water stays the light blue while I add the drops, and then stays blue when I shake, only eventually turning purple but a lower purple on the scale.

Is this a sign my cycle is almost done??

Thanks.

[SkarloeysMom]

Sounds like its almost done. Check for Nitrates and see if you have any. That may answer your question.

[sergo]

yes they will start to drop some for a few days and then all of a sudden they will be gone. make sure you keep adding ammonia to the tank daily until you finally put fish in it or you will lose your bioculture. it wouldn't hurt to start testing for nitrates either.

[Chaindriven]

Since your fishless, higher temperatures of 86° - 95° F ( 30° - 35° C) can be used for optimum bacteria when cycling without fish, but you must stabilize the aquarium slowly back to lower temperatures before you add fish.
You can speed and enhance the nitrification process by introducing a starter culture of bacteria. I always seed my new aquariums with some gravel or filter media with existing bacteria from an established aquarium. I have hear of some fishkeepers using commercial preparations of nitrifying bacteria, there are several different brands available. God Bless and good luck.

[naiku]

Ok, so I keep monitoring this and along with my nitrites now being very close to zero, I also have high nitrates............ but I still have ammonia of around 4.0 on the scale............ which is a little odd. I have not added any ammonia for a couple days as it has stayed right around 4.0............ I am debating a PWC, but not sure if this will remove some of the nitrites / nitrates that I need to get the cycle complete.......... would it make sense to do a water change?

I know that my nitrites spiked, as they were way off the scale in the purple color, and have only in the past couple days dropped almost to nothing. Maybe I added too much ammonia the last time I added some........... either way would a water change be a good idea? or no?

[sergo]

not much need to do a pwc if you don't have fish. the bioculture will convert everything over. you should be adding about half of the ammonia that you were.

[naiku]

not much need to do a pwc if you don't have fish. the bioculture will convert everything over. you should be adding about half of the ammonia that you were.

Thanks, I did not know if it was worth doing the PWC or not.......... there are no fish in there so will wait a few more days. Hoping that this is the end of the cycle though!! Will be glad to no longer have an empty tank and am about 99.9% set on what to stock it with.

[sergo]

well when nitrites and ammonia hit zero and stay there for a couple of days you'll be able to put your fish in. there have been some experiments where someone has fishless cycled a tank and put their entire stock in at once with no problems. i personally wouldn't suggest it but when you fishless cycle you make a very large bioculture that can easily handle half of your total stocking.
i would do half and see how the tank reacts then make a week or so later add the other half. you'll probably get some different opinions on this though.

[RobbieG]

If you do half at once you may want to add the rest gradually to give the tank and the other fish a chance to adjust.

The bacteria that develop during cycling can only go a few days without food (ammonia etc) if you add half as many fish as the bacteria handle you will lose some in a week. Doubling the bioload at that point would likely cause a minicycle.

Also - even if tank can handle the bioload your fish may not be happy with the addition of a large number of tankmates all at the same time.

[gm72]

I agree with both of the last 2 posts. I usually add half the stocking, then another 25% about 2 weeks later and another 25% another 2 weeks later. That is, provided it isn't a monster tank but rather a tank up to 55 gallons.