Backyard Aquaponics
A place to discuss aquaponics

Cycling start date = 3/28

After some reading and research, I fond some janitorial ammonia and introduced it to my tank until the test read ~6-7 ppm (I was aiming for 5, but overshot it during my initial dosing). 5ppm is what most articles and vids I have read said you should start at.

Today's (3/31) reading's are at

pH = ~7.4-7.8
Nitrite = 0
Nitrate = 0

These numbers have remained fairly consistent with the exception of the ammonia slightly decreasing from the day 1 reading.

Further reading on this forum seems to indicate that my ammonia levels should be MUCH lower (~1-2ppm) and that high ammo levels could retard system cycling. Are you supposed to start high, wait till nitrites then lower your ammo levels?

Can anyone help a totalnoob get their facts straight?

It also takes time. It's only been a few days. It normally takes me a month+ during the summer and up to 3 months during the winter. When the tanks are at 75 degrees its pretty quick.

Yes, too much ammonia will slow it down at around 5ppm. So first initial dose is around 4ppm and doses after that are 1ppm. Do a partial water change and get the ammonia down to around 4 ish. Once you get the nitrites only dose about 1ppm of ammonia and only dose more ammonia when you do not read any ammonia. It always irritated me when my nitrites were off the scales. I normally do partial water changes when readings go off the charts. I like to keep the ammonia and nitrites under 4ppm.

Second, your nitrobactor/spira will not convert nitrites into nitrates when ammonia is present. Dosing of the 1ppm ammonia is just to feed the nitrosoma and during that time the nitrobactor/spira won't be converting or growing.

Watch your PH during this time. You are adding more ammonia and nitrites than would normally be present. My PH always crashes when I do a fishless cycle and when it hits around 6and under the whole thing stalls out.

When you dose 1 ppm of ammonia and the next day you have no ammonia or nitrites and only nitrates you are ready for for fish. I always hit it with 2ppm and make sure it's all gone to be sure. You can add plants now. They will grow and do fine. Plants can absorb all forms of ammonia just not as efficiently as nitrates

Under optimal conditions it takes 24hours for nitrosoma to double culture size and about double that for nitrobactor/spira. Keep the water well oxygenated also.



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Owe, dont get frustrated with it. Have patience. It will cycle. Resist the temptation to get fish or rush it. After a fishless cycle you will have a strong bio filter.

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Thank you. I am certainly waiting until the bio filter is established, I just don't want the cycling to take even longer. Sounds like I overdosed.

I know that the cycle itself takes a while, I am just afraid i set it back even further by over dosing. Do you recommend i just wait till i get to 1-2 ppm and keep it there?

If you are still sitting on 6 to 7 ppm ammonia I would do a partial water change to bring it down to about 4ppm. 5ppm is the max so give your self some wiggle room. Wait till your ammonia reads zero before you dose again.

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You didnt hurt anything. Within the week you will see nitrites.

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As mentioned above:

Cycle start: 3/28

Today's 4/7 readings:
Water temp: 80F
pH: 8 (This is down from yesterday were it was 8.8! It spiked all of a sudden. Added some water to the system to get this down)
Ammonia: 1ppm
Nitrite: 0
Nitrate: 5

This is where I am confused. Throughout my entire testing, i have registered no nitrite at all. My understanding is that nitrite shows up first, then spikes, then you get nitrates.

Well, my system seems to be doing the opposite lol. No nitrites but yes nitrates, wth? There's no way the system cycled in 1 week with just ammonia, is there?

I'd cross check the result just to be certain. Cycling does go faster with warmer temps but I'd expect to see the nitrite spike unless there is something wrong with your test kit or there were already an adequate number of the bacteria present that convert nitrite to nitrate. This happens when starting back up an aquaponics system after a long period without use because the bacteria are still present.
Other types of bacteria can also cause this by out competing the ones we want - this would only be expected if their is a significant carbon source that could change the carbon to nitrogen ratio to favor these bacteria.

Thanks for the reply. I am definitely going to retest and re-check the readings this afternoon.

The system I set up is a "virgin" system, if you will. I have never done aquaponics (so no prior gb or media) and the fish tank is used but was scrubbed and cleaned prior to my installation.

The system did run for quite some time just with water (no ammonia or attempt to cycle it) while i was setting it up and testing that everything worked. Could the cycling have happened during that time?

As far as carbon source, I am not too familiar with that but would presume it comes from your grow media?

I am using expanded clay pellets and lava rock. I checked the lava rock with vinegar prior to use to ensure it would not affect the water pH, however, i never tested the clay. Are there other sources where carbon could be coming in that I am unaware of?

To test out the cycling, add the ammonia to 2ppm and see if it's gone in 24 hours. If your system is turning 1 or 2 ppm of ammonia into nitrates in 24 hours you are ready for fish. Just keep dosing it daily until you get fish to keep the bacteria alive.

You won't really start cooking through your PH for a while. It will and does come down it just might take a bit.

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Cycling is one of those fickle things. Depending on environment it can take take a week to months. It is not unheard of to cycle in a week.

The bio filter just might not be strong yet. Or it could be really strong. I never see nitrites. Only trace ammonia and nitrate. Adding 2ppm of ammonia and it being gone in 24 hours with out any nitrites is a sign of a healthy strong biofilter.

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Interesting, I had never heard of cycling being able to be done that quickly. Does give me hope that mine is just super fast jaja.

Funny you mention the ammo conversion as a benchmark as it is something I noticed. Previously, 2 cap fulls would place my levels at 5ppm. Now, i add 2 cap fulls and test 24 hours later and i am back at 0 ppm.

I will continue to dose until fish and cross fingers i get some growth!

Any thoughts on starting seeds directly in the GB vs. starting them elsewhere then planting?

I have always had problems getting germination in the grow bed. I used to use the peat moss plugs, worked decent but the moss would hold water like a sponge. I switched to coco coir and vermiculite and really like it. I use the plant cells from the nurseries. Water from the bottom with aqauponics water. Once the plants get 2 true leaves I put them into the grow beds.

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Based on your description your system is cycled. Sounds like either the spike of nitrite was missed or the test kit isn't working. It's possible to have nitrate and nitrite in your tap water but I don't know if this is your situation. As mentioned by others the initial bio-filtration is a bit delicate. You've done a good job of beginning to building up the bio-filter but it's a good idea to watch your ammonia, nitrite and nitrate just to see how you're doing and to prevent a fish kill from getting a spike.

I've had better luck with seeding outside of the AP system and then transferring in later (damping off can be a problem in cooler weather). When the weather is warm I can direct seed and it works OK. When damping off (which is caused by a fungus) is a problem, it helps to grow the plants up to around 2"pot size because it makes them less susceptible. For some plants it makes sense to sprout them before planting them - I use ziplock bags with a damp piece of paper towel for this and then transfer to media once they sprout - This is a pretty good video https://www.youtube.com/watch?v=dirz0WIMQi0. Transfer however you want, no media sometimes works or into whatever works for you - most people rinse the media off before putting into the system (I do sometimes but not others lately I've been using peat pellets in the DWC and I just plop them into a 2 inch net pot- I'm not trying to grow commercially so the cost isn't really a factor).