Advice/help with prawn fishless cycling

HI all

Total beginner to this and have read much about fishless cycling, some of it conflicting. I am trying to cycle a new Arc 20L tank, with gravel and the in-tank filter it came with (no heater yet, it's in the post) using one raw prawn.

I started 5 days ago. 3 days ago the water went cloudy and I took these readings:

PH = 7.5-8.5
Ammonia = 2.0 mg/l
Nitrite = 0.1 mg/l
Nitrate = 10 mg/l

Today I tested the water again and got the following results:

Ammonia = 4.0 mg/l
Nitrite = 1.5-4.0 mg/l (now I know what other people are talking about when they have trouble matching colors)
Nitrate = 50 mg/l

So far I think things are going as they should be, but please shout if you disagree. My question is whether I remove the prawn at this point as the ammonia has reached 4.0 mg/l. And if I do, do I need to stick it back in at some point before the cycle ends?

Any comments, thoughts, tips, etc. greatly appreciated!

 

Welcome to FishLore!!

Looks like things are going well.

At this point, it's your choice if you want to remove the prawn.

You've got ammonia to continue to feed the bacteria.
If you remove it, and the ammonia drops to 0 and you still have a nitrite reading, be sure to add a source of ammonia.

If your ammonia and nitrites drop to 0 and you still have nitrate readings, do a big water change to get the nitrates to around 10 and you're good to go.

Good luck and congrats on going fish less.

 

Sounds like you are past being cycled if I'm correct... 50 mg/l nitrate would be a very high nitrate reading. Take the prawn out now and the levels should balance out... meaning ammonia and nitrites should go down to 0, the nitrates should be less than 20 mg/l so if they don't come down you may have to do a water change as Lucy mentioned.

 

If there was enough bacteria to be considered cycle or passed cycled, the ammonia and nitrites would be 0.

The OP only started cycling 5 days ago.

 

Not if the ammonia source (in this case rotting organics) continued to raise, this would cause a constant bacteria bloom trying to keep up with the organic matter.

(I'm basing this on the nitrate levels present in the tank, 50ppm is fairly high)

 

We'll have to respectfully disagree with each other on this one.

In a cycled tank with a strong bacterial base, you could add 4ppms of ammonia and except it to drop to 0 in 24 hours.

 

True but that's not a constant source if you only add it once lol, the prawn is holding the ammonia level that high by rotting... the nitates (50ppm) indicate that it probably has a sufficient bacteria level to sustain fish as stable nitrate levels are under 20 ppm.

 

Thanks both! Appreciate the advice. ;D

I've taken out the prawn and will let everyone know how it goes. I know that what I want to achieve is 0 ammonia and 0 nitrite. And the max nitrate at any given time is 10? At what point does too much nitrate become a bad thing?

 

Max nitrate should be less than 20, that's generally considered safe =)

 

Max nitrate should be less than 20, that's generally considered safe =)

Hey, we agree! lol

 

Hey, we agree! lol

LOL, I'm not disagreeing with you at all Lucy... I see your point that a "cycled" tank has enough bacteria to nullify ammonia to 0, but that's with a fishload that only produces a certain amount of waste per day. A rotten shrimp produces waste constantly until it is completely broken down, so the bacteria levels may already be high enough to sustain a fish population (going by the nitrate reading of 50ppm)

 

Hmmm... I see what you are both saying. I'll see how it goes without the constant decaying prawn. While I have you both here, another question -- I'm thinking of replacing the filter that came with the tank with a different one that's quieter and has flow control. I'm thinking that to do that right I need to put it in the tank and run it alongside the one that's in there now for a few weeks in order to build up a bacteria colony in it? Or would you suggest just putting in the media (sponge filter things) for a few weeks and then switching filters? Taking things a little off topic I know...

 

Either way will work, its completely up to you on what way you want to do it =)

 

Hmmm... I see what you are both saying. I'll see how it goes without the constant decaying prawn. While I have you both here, another question -- I'm thinking of replacing the filter that came with the tank with a different one that's quieter and has flow control. I'm thinking that to do that right I need to put it in the tank and run it alongside the one that's in there now for a few weeks in order to build up a bacteria colony in it? Or would you suggest just putting in the media (sponge filter things) for a few weeks and then switching filters? Taking things a little off topic I know...

I'd go for putting the old filter media in the new filter but either would work.

 

I'd go for putting the old filter media in the new filter but either would work.

That would be faster

 

I'd go for putting the old filter media in the new filter but either would work.

Doh! Why didn't I think of that? (no emoticon for slapping forehead)

Thanks again Lucy and Clinton. I'll be back at the weekend to post results.

 

Doh! Why didn't I think of that? (no emoticon for slapping forehead)

Thanks again Lucy and Clinton. I'll be back at the weekend to post results.

Sure there is.... LOL!!

You're welcome and good luck!!

 

OK folks. I'm back. Took out the prawn on the 8th and took water readings today that don't seem to have changed much:

Ammonia = 4.0 mg/l
Nitrite = 4.0 mg/l
Nitrate = 50 mg/l

By now the ammonia should be going down right? Has something gone wrong or am I just being impatient...?

 

I'm sorry if I missed this, but are you using strips or a liquid kit?

 

I'm sorry if I missed this, but are you using strips or a liquid kit?

HI Lucy. I'm using a liquid kit -- Interpet Easy Test -- that has tablets for PH, Ammonia, Nitrites and Nitrates.

 

Personally, I'd let it ride.
The cycle is only about 2 weeks old right?

 

Not even. I'm wrapping up week one. I was wondering if I should get some Safe Start to help move things along but having just read the thread about it I think it won't work until the ammonia goes away. So I'll give it another week and see what happens...

 

Cycling usually takes close to a month or so.
Hang in there.
Other members might have different suggestions, let see what they have to say.

Oh, adding aeration and upping the heat can help move things along too.

 

Oh, adding aeration and upping the heat can help move things along too.

Thanks. Yes, only recently got the heater going and am now aerating. I think I got ahead of myself when I saw the high level of nitrates.

 

Hello again. Well, now I'm confused. Here's why:

Aquarium water test done today, 2 weeks into cycling (prawn still removed):

Ammonia = 2.0
Nitrite = 1.5~4.0
Nitrate = 50

Tap water test done today (first time I've done this):

Ammonia = ~0.1
Nitrite = 0
Nitrate = 50

So, either I have bizarre levels of nitrates in my tap water or my water testing kit is useless (btw - Lucy, I said I had a liquid kit and that's not correct... you use a tube to capture water and then drop tablets in and shake).

Can anyone shed light on whether my readings are totally skewed, whether the cycle is actually just only starting (because I get the same level of nitrates in tap water as I do testing the tank), or something else is going on?

 

Your tap reads 50 nitrates?

 

Your tap reads 50 nitrates?

yes... i'm going to retest tomorrow but that's what it read today

 

It would be very odd for your tank nitrates to read 10 on the 8th and 50 now if you're getting a 50 reading from your tap too.

If it weren't for that, I'd say you were just about cycled.

If the tap is a correct reading either something in the tap water has changed, it was tested wrong or maybe a faulty test kit.

Let's see what others have to say.

 

I don't think I'm trusting that test kit. Can you get the API test kit? That will be your most accurate readings.

I cycled with raw shrimp and it took a month for me to cycle. So I believe something is awry.

 

HI both - yes, I think something may be up with the test kit. I didn't go for the API liquid for cost reasons. I have a different set of tablets and will see if the nitrates change (I agree Lucy, strange it started at 10).

Danni, out of curiosity did you leave the shrimp in the whole time?

 

I did leave one in the whole time...when it got too funky- I replaced it. I would leave it out for a day and see where I was at with my numbers. Once I showed 5 Nitrate and 0 on everything else- I pulled it out for good and changed the water.

It did take a good month though to get there- you get some pretty crazy numbers going through this.

 

Thanks Danni.

Another question for the general public. Had similar readings last night as before so cycling continues. But I've lost a lot of water in the process due to evaporation and using it for tests (I guess). I'd say I've lost about 25%-30% water since I started.

Will I mess up the cycle process by adding water to the tank?

 

Nope, just make sure it's dechlorinated.

 

I second what Lucy said...keep it full.

 

Thanks both. Have filled the tank up and will take some more readings. Put in two live plants and some moss as well, so hopefully all will come together soon.

 

HI folks. Back again. Readings looking (I think) encouraging:

Ammonia = 0.4
Nitrite = 1.5 mgl
Nitrate = 25~50 mgl

Two questions:

1. At this point I'm getting impatient and am wondering whether I can add something like Tetra Safe Start and then a fish this weekend. I read the sticky Lucy posted, and the ammonia level seems OK (I'm hoping it continues to reduce) but are the high nitrite and nitrate no gos?

2. There is a thin layer of white slime on the top of the water in the tank. Kind of looks like drops of oil on water except white, with little white specks floating in them. I did add plants and a coconut cave last week. Anyone have any idea what this is? Algae forming? Leftover prawn gunk? The filter is filtering away so not sure what's happened?

As always, please post your thoughts. Thanks.

 

Your almost there it looks like- don't get the TSS- it would be too much at this point and could backfire from what I have read. Change water like half of it. How high is your temp in the tank right now?

The white slime is probably lack of surface disturbance on top. I have it on my Betta tanks. It really isn't harmful unless it's foam like soap- and you used soap in your tank. You can add an airstone if it bugs you and it will go away with that.
What type of filter is on this tank? It would give me a better idea of the white problem.

Patience is a virtue my dear- you are seriously almost there. See what your numbers are tomorrow- change a good deal of water tonight.
Is the nasty shrimp still in there?

 

Your almost there it looks like- don't get the TSS- it would be too much at this point and could backfire from what I have read. Change water like half of it. How high is your temp in the tank right now?

The white slime is probably lack of surface disturbance on top. I have it on my Betta tanks. It really isn't harmful unless it's foam like soap- and you used soap in your tank. You can add an airstone if it bugs you and it will go away with that.
What type of filter is on this tank? It would give me a better idea of the white problem.

Patience is a virtue my dear- you are seriously almost there. See what your numbers are tomorrow- change a good deal of water tonight.
Is the nasty shrimp still in there?

Thanks for the TSS tip Danni. The temp is around 26c/77/8 F. The filter is a classica 200 (flow rate of 200L per hour) that came with the tank (20L/5+ gallon).

I'll do a water change tonight. I've ordered some Prime and had the cunning plan of dosing the water on Friday with Prime to kill of the Amonia, Nitrites and Nitrates, and then add the TSS... but maybe just the water change and prime will do.

Oh, and took out the shrimp after week 1 when the Ammonia was 4.0+.