I have a 50-gallon wide tank and all associated materials. On November 1st, my tank had tap water chemistry (meaning 0 ammonia, 0 everything); I had just set up my tank.

I added Stress Zyme by API and stress coat to dechlorinate and dechloramine the water. It also added beneficial bacteria - I have driftwood, slate, and moss in my tank. I have marbles on top of my gravel.

At two weeks after set-up (Nov. 14) and adding 30 drops of ammonium chloride weekly, the tank has 0.5 ppm ammonia, no nitrites, and 40ppm nitrate. Is my tank done cycling? Should I add more ammonia? I added a rotala plant two days ago.

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    So did you add the chemicals today? Nov 14, 2013 at 23:11
  • No I added the chemicals November 1st.
    – Don Larynx
    Nov 14, 2013 at 23:19
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    Have you done anything since then besides the plants? Nov 14, 2013 at 23:20
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    Nope, I've only been adding decor and adding ammonia weekly. Now I am noticing a nitrate buildup with no nitrite meaning that the tank is completing its cycle. However I read most tanks take like 6 weeks to cycle, so I'm just making sure.
    – Don Larynx
    Nov 14, 2013 at 23:21
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    @DonLarynx Your water quality is good for the bacteria -- cycling can be more unstable in soft, acidic, cool water. Looking at the label on Proper pH, I don't think it will soften your water, just lower the pH -- and depending on the fish you're looking at, you don't necessarily need to do either.
    – toxotes
    Nov 15, 2013 at 14:01

3 Answers 3


Unfortunately I'd say no, not if you still have that much ammonia showing up. The rule of thumb I've seen is you should be able to add 2ppm ammonia and have it completely converted to nitrates within 24 hours.

It's odd that you're seeing ammonia and nitrates at this stage: you tend to see the ammonia-consuming bacteria show up very quickly (see the graph here), then the ammonia disappears but nitrites skyrocket and linger forever. They might not actually be coming from your denitrifying bacteria: do you know for a fact that your tapwater has 0ppm nitrates? If you haven't done so already, mix up a batch of new water as if you're doing a water change, let it sit about half an hour, and then check to see what your starting conditions really are.

I'm also skeptical because you've been dosing the ammonia weekly. Were you testing to see when the ammonia started dropping to add more? If not, your NH3-consumers may not have had enough food to get established. (Two thumbs up for dosing your NH3 by the way: it's a lot more work than using fish, but so much safer for them, and more reliable.)

I'm not convinced many of the bottled nitrogen cycle starters are very reliable, by the way. Older recipes don't actually have Nitrospira, the bacteria that consumes NO2, because until a few years ago, other dentrifiers were thought to be much more important to the aquarium nitrogen cycle than they really are.

  • My nitrates and ammonia came up to 0 ppm in the tap water.
    – Don Larynx
    Nov 15, 2013 at 1:54
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    Ah, that's good then. I'd still say wait until NH3 and NO2 are both stable at 0, though.
    – toxotes
    Nov 15, 2013 at 13:56

At this stage, I would look to add fish and stop artificially adding ammonia to the system. Ideally, you want to start small, with a few hardy fish added to the tank, much less than your tank is expected to handle, and then begin adding more fish over the next few weeks as you system equalizes from the prior additions.

Basically, you now want to slowly encourage the bacterial growth in the tank towards the amount needed to sustain the quantity of fish you intend to keep. It's best to do that with the fish. Don't overcrowd, make sure that you slowly build up to the recommended capacity of the tank and don't add too many at once.


Make sure the bacteria levels are correct for whatever type of fish your adding also make sure the filtration system is correct as well as anything in the tank such as plants etc have all there bacteria levels up.

I think when setting up a tank Anything but Gold fish type species, you need to wait 48 hours that what I remember anyway

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