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Just don't understand the cycle I guess...


314tank

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Hi again all --

 

I'm cycling a new 14 gallon biocube and the results of my water changes only 5 days in are contrary to everything I've ever known/read about the nitrate cycle.

 

I used live sand (CaribSea Ocean Direct Live Sand) and 15lbs of cured live rock. I also have a media basket that I built with filter floss/purigen/chemi pure. I started the tank on Saturday and already today, I am getting water tests that show a very small amount of ammonia, ZERO nitrite, and 40ppm nitrates.

 

Again, everything I've ever read tells me I should see ammonia spike into the green (never happened, never tested above .50ppm), then see nitrites spike (never measured anything but 0 ppm) and then nitrates spike, indicating the cycle is complete and I can add a fish (nitrates have been registering since yesterday and climbed again today).

 

Why isn't this cycle going anything like I expected it to, and can the cycle really be complete to the point that I should do a water change and add a fish?

 

So confused here.....I took pics of the water change results and of the tank. Any help is greatly appreciated!!!

 

 

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I didn't know it made that big of a difference...like I said, everything I've ever read makes it sound like no matter what, you're going to cycle for 2-4 weeks....I guess what I want answered before I go killing fish is - am I safe to assume the cycle is complete and I can water change/add stock??

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Nope...you added a fully stocked set of microbes to handle what little biomass was in your tank in the form of live sand a cured rock.

 

I would still use caution...if you add a lot of C or N source to the tank too quickly, you might overwhelm the biofilter.

 

Do you have diatoms yet? If so, add CUC...then in a week if everything looks good you can add a small fish or tester coral.

 

Add slowly, as your growing biomass will require your biofilter to grow over time.

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Diatoms are just beginning to show slightly...I suppose let them continue to bloom a bit and then add the CUC? Thanks for the advice here - makes a lot of sense

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5 day cycle? Is that even possible? I would be a bit more patient if I were you and check your levels in a few days before adding any fish.

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I would take out the chemipure and purigen for a few days and retest. You usually do not run any kind of filter while cycling. Chemipure and purigen can artificially control levels, so you don't have a good idea of what your actual biofilter is. Purigen controls ammonia nitrite and nitrate levels. Take it out (and the chemipure) and let it sit for a few days and retest.

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I didn't know it made that big of a difference...like I said, everything I've ever read makes it sound like no matter what, you're going to cycle for 2-4 weeks....I guess what I want answered before I go killing fish is - am I safe to assume the cycle is complete and I can water change/add stock??

 

So first thing the "cycle" is just that - it's not a one time event and you're done. Rather it's a continuous process that has to re-adjust each time you make a change to the tank. What most people seem to consider the "cycle" is simply the establishment of all the necessary bacteria to break down organic waste (the bio filter). Whether you add a piece of live rock or a cap full of bottled bacteria or simply wait for the bacteria to populate the water over time it's all the same. The difference is the time it takes for the bacteria to be present in sufficient numbers as to support a bio load (fish, CUC, etc...).

 

As mentioned if you add fully cured quality LR and sand to a tank bacteria are added instantly and usually in decent numbers (again depending on how long the rock has been cured/cycled). So it's not at all surprising that you are showing the test results you are. The goal now is to build up the bio filter to the point where adding livestock won't surpass it's ability to process the additional waste in the system. To do this add a small amount of pure ammonia to your tank. It's generally accepted that if your bio filter can process 2-3ppm of ammonia in 24 hours then it's ready for a reasonable bio-load. Search "Ammonia dosing calculator" and enter your water volume and it will give you a good indication of how much ammonia to add to get to about 3ppm. After a few minutes test the water and you shouldn't be surprised at the results. It may differ slightly due to test kit inconsistencies though. Wait 24 hours and test again. If you have no ammonia or nitrite and your nitrates are reasonably low then you're good to go.

 

If you still register ammonia after a day you can continue dosing ammonia for a week or so which should rapidly build up your bio-filter. Don't let the ammonia creep up above 4-5ppm though or it can have a retarding effect. Using this method you should be able to pretty much stock your tank in one go (within reason).

 

If you don't want to do ammonia dosing you can put your trust into the bio filter you already have and just start adding things slowly and methodically. Once you test 0 ammonia 0 nitrite and low nitrates you can add your CUC then wait a week to let the cycle adjust, test again, and add a fish. Then wait another week, etc...

 

Finally, if you want instant results you can add bottled bacteria and I believe the instructions say you can add fish in a day or so.

 

There are other methods as well, but more time consuming and because ammonia is so cheap and that method is so reliable it's hard to beat.

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So first thing the "cycle" is just that - it's not a one time event and you're done. Rather it's a continuous process that has to re-adjust each time you make a change to the tank. What most people seem to consider the "cycle" is simply the establishment of all the necessary bacteria to break down organic waste (the bio filter). Whether you add a piece of live rock or a cap full of bottled bacteria or simply wait for the bacteria to populate the water over time it's all the same. The difference is the time it takes for the bacteria to be present in sufficient numbers as to support a bio load (fish, CUC, etc...).

 

As mentioned if you add fully cured quality LR and sand to a tank bacteria are added instantly and usually in decent numbers (again depending on how long the rock has been cured/cycled). So it's not at all surprising that you are showing the test results you are. The goal now is to build up the bio filter to the point where adding livestock won't surpass it's ability to process the additional waste in the system. To do this add a small amount of pure ammonia to your tank. It's generally accepted that if your bio filter can process 2-3ppm of ammonia in 24 hours then it's ready for a reasonable bio-load. Search "Ammonia dosing calculator" and enter your water volume and it will give you a good indication of how much ammonia to add to get to about 3ppm. After a few minutes test the water and you shouldn't be surprised at the results. It may differ slightly due to test kit inconsistencies though. Wait 24 hours and test again. If you have no ammonia or nitrite and your nitrates are reasonably low then you're good to go.

 

If you still register ammonia after a day you can continue dosing ammonia for a week or so which should rapidly build up your bio-filter. Don't let the ammonia creep up above 4-5ppm though or it can have a retarding effect. Using this method you should be able to pretty much stock your tank in one go (within reason).

 

If you don't want to do ammonia dosing you can put your trust into the bio filter you already have and just start adding things slowly and methodically. Once you test 0 ammonia 0 nitrite and low nitrates you can add your CUC then wait a week to let the cycle adjust, test again, and add a fish. Then wait another week, etc...

 

Finally, if you want instant results you can add bottled bacteria and I believe the instructions say you can add fish in a day or so.

 

There are other methods as well, but more time consuming and because ammonia is so cheap and that method is so reliable it's hard to beat.

Preach it brother! Excellent post.

 

My IM20 is bare bottom, only cured live rock. Used a tsp of reef roofs to kick off cycle and provide a C and N source to feed the bio filter.

 

Not so much as a blip of ammonia or nitrite. Added cuc after robust diatom bloom, few small corals, small fish one at a time...

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Thanks again for the advice -

 

I started ammonia dosing on Wednesday and with 1 tsp, got up to 3ppm. Waited 24 hours and tested....I had .5 ppm of ammonia, .25ppm nitrite, 80ppm nitrate. SO - today I added a bit more ammonia since it didn't all go away in 24 hours with the first dose. I'm going to keep dosing ammonia and keeping the level about 3ppm, testing every 24 hours until one day it's completely gone...

 

I like the explanation of the cycle as a gradual build up - LFS always make it seem so concrete and like once it's done, it's done. As I'm learning, that's not really the case.

 

Update to come...

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I used established live rock from a running tank and never had the slightest of cycles. Everything was stable from day one. I'd go slowly on adding fish like everyone else said because everyrime you increase the bio load the bacteria have to "catch up" to the new bio load.

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