What is a stealth cycle and did my tank do this?

[N3PTUN3]

Hi

I've had a 125 litre tank since 1 April 2012. I did a fish-in cycle. It took a couple of weeks before I could detect anything in the tank. Eventually I had 0.5ppm ammonia, but it never got any higher. For the last three weeks the readings have been been fairly static at

NH3 = 0.25
NO2 = <0.1
NO3= <5
pH = 7

My local supplier has told me the tank probably did a 'stealth' cycle and that this is good. Has anyone heard of this?

thanks for reading!

[aqua_chem]

I believe what you are referring to is a technique wherein heavily planted tanks with fast growing stem plants are stocked with a few fish and allowed to run for the duration of the cycling process. The fast growing plants absorb most of the ammonia before it gets to a critical level for the fish, but there is still ammonia left to let the bb establish.


I kind of sounds like you didn't dose your tank with any ammonia to begin with to start your cycle.

[N3PTUN3]

No, I didn't dose with ammonia. I had fish in it.

[aqua_chem]

How many, and any plants?

[N3PTUN3]

8 zebra danios, and only synthetic plants at the beginning, until i got the first nitrate reading.

Tank contents has changed now.
I lost 4 zebra danio because they got trapped between the filter casing and the glass. Rearranged the gravel to prevent them getting access.
I then added 6 silvertip tetras. Two of them died after being bullied by a dominant male. I then added 3 baby bristlenose catfish and later, 6 cardinal tetras. The cardinal tetras must have had a disease because shortly after purchase, three of them died along with 2 more zebra danios .

Anyway the tank now has 2 zebra danios, 4 silvertip tetras, 3 bushynose catfish and r cardinal tetras. all doing well (especially the catfish, which are growing like crazy).

Water chemistry hasn't really altered much throughout.

[librarygirl]

Hm, after two months you should be cycled, or close-to. Have you tested your tap water for ammonia, nitrite and nitrate? What test kit are you using?

[N3PTUN3]

Hi there

I live in the Scottish Highlands so the water quality is pretty good. No nitrate, nitrate or ammonia, but it is very soft. Also pH is 6.5. (but 7 in the aquarium)
I'm using the nutrafin liquid test kit for everything except ammonia (used that one up so changed to API).

[librarygirl]

You're overstocked actually and probably overwhelmed the tank with too many fish at once now the bacteria need to multiply enough to sustain the current load which is probably why it's taking a bit longer. What filter is on the tank? Are you changing out media or cleaning it in tap water or anything (you shouldn't do either)? I'm assuming you're dechlorinating the water prior to water changes, right?

[N3PTUN3]

Originally Posted by librarygirl

You're overstocked actually and probably overwhelmed the tank with too many fish at once now the bacteria need to multiply enough to sustain the current load which is probably why it's taking a bit longer. What filter is on the tank? Are you changing out media or cleaning it in tap water or anything (you shouldn't do either)? I'm assuming you're dechlorinating the water prior to water changes, right?

I didn't realise I was overstocked. I have 125 litre tank with twelve small fish in it. and they weren't all added at the same time. Do you mean overstocked for this stage in the cycle, or overstocked in general? Wouldn't my ammonia readings be higher if I had a stocking issue? The tank is a Juwel Rio 125, which has an internal filter housing with several filters in it. So far, I have only changed the top white filter a couple of times. I have most often just rinsed it in tank water during changes. And yes, I always dechlorinate the water before adding it to the tank.

[librarygirl]

Originally Posted by N3PTUN3

I didn't realise I was overstocked. I have 125 litre tank with twelve small fish in it. and they weren't all added at the same time. Do you mean overstocked for this stage in the cycle, or overstocked in general? Wouldn't my ammonia readings be higher if I had a stocking issue? The tank is a Juwel Rio 125, which has an internal filter housing with several filters in it. So far, I have only changed the top white filter a couple of times. I have most often just rinsed it in tank water during changes. And yes, I always dechlorinate the water before adding it to the tank.

They're small now but they'll grow. The problem is the 3 catfish; they can be messy which adds to the bioload. Once you're cycled just keep up a good water change schedule (50% weekly) and you should be ok. I'm not sure you'd be able to add much more to the tank though.

Also what filter is on the tank? I looked up the Juwel Rio 125 (which is about 33 US gals) and it says it comes with a juwel compact bioflow 3 filter? is that right? Because from what I can find that filter is only rated for 18 uk gals (about 21 us gals) so that's not enough enough for your tank; I could be wrong though, just something to think about for the future. You could add another filter which wouldn't hurt. Most filters that come with kits are just barely enough for the tank size. Adding another filter will also give more surface are for more bacteria to grow on.

I'd watch your PH. If it's 7 in the tank that's fine, but if it drops to below 6.5 then the bacteria will suffer which can prolong the cycle too.

[N3PTUN3]

Originally Posted by librarygirl

They're small now but they'll grow. The problem is the 3 catfish; they can be messy which adds to the bioload. Once you're cycled just keep up a good water change schedule (50% weekly) and you should be ok. I'm not sure you'd be able to add much more to the tank though.

Also what filter is on the tank? I looked up the Juwel Rio 125 (which is about 33 US gals) and it says it comes with a juwel compact bioflow 3 filter? is that right? Because from what I can find that filter is only rated for 18 uk gals (about 21 us gals) so that's not enough enough for your tank; I could be wrong though, just something to think about for the future. You could add another filter which wouldn't hurt. Most filters that come with kits are just barely enough for the tank size. Adding another filter will also give more surface are for more bacteria to grow on.

I'd watch your PH. If it's 7 in the tank that's fine, but if it drops to below 6.5 then the bacteria will suffer which can prolong the cycle too.

Ok, now I'm totally confused. I tried using this website to help me with stocking advice

AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor.

It has an online interactive stocking advisor. You just put in your tank, filter and fish details and it tells you what you whether you are overstocked or if you need extra filtration.

Unfortunately my filter isn't there. I do have the bioflow 3.0 compact H, but it has a 600 pump. I assumed this would mean a decent enough flow rate, but perhaps not.

To be honest I get a bit confused about filters and pumps and flowrates and filtration capacity. The tank has a stack of filters in it. 2 very fine textured blue sponges, one coarse textures blue sponge, a green nitrate removing sponge, a mesh box that looks like it's filled with little stones, a black carbon filter (which I have removed) and a top white filter made of fluffy stuff (sorry, I'm not being very technical) There is enough room to add another filter now that the carbon has gone. I also read somewhere that perhaps I don't need the nitrate removing sponge. Hmmm, maybe that's why my nitrate is staying low.

When you say I need more filtration do you mean I need more filter media or do I need an extra pump or a stronger pump?

Apologies if I'm being really dumb.