Just exactly what is a 'cycled' tank

[JT101]

OK, this is really going to expose my "newbie" status:

I have an AquaPod 24 that was started with Nutri-SeaWater, 18lbs. of live rock and 204lbs. of live sand on 6/14/07.

My dilemma is, I honestly do not know what a fully "cycled" tank appear to look like through the eyes of the normal chemical tests. I have been checking my chemicals every few days but I don't know what I am looking for.as a jumping off point. I mean, I understand the basics, like I know the ammonia and nitrates should be as low as possible, but exactly what does "cycling" have to do with this? Do certain chemicals rise and fall at a certain predictable rate, then finally settle out?

If so, then can someone help me with the approximate schedule?

I have seen numerous times that six weeks is enough time to cycle a tank, but I won't know what that means when I get there (my tank will be 5 weeks old this Friday).


Thanks
John

[BigAl07]

cycling is the term we use to describe when a new tank (zero bactieria) begins the process of "building" it's bio filter. You'll have to go through the whole Cycle of amonia to nitrite to nitrate. That's the "cycle". Your tank has to establish it's beneficial bacteria to a level that will completely convert all existing "stuff" from amonia all the way to nitrate. You'll see a Spike of Amonia first. Then a few days later as the bacteria increases you'll see Nitrie Spike. then with time nitrate and then it should start to level off with proper care. Even after the tank is "cycled" you'll still get "mini-cyles" as new stuff is added to the tank. This is normal as the bio-load increases so too will the beneficial bacteria. The key is to have MINI cycles and not HUGE fluctuations within your tank.

A tank cycle and take anywhere from 4 weeks to a few months depending on MANY variables. This is the time to learn to test and "understand" you tank and how it reacts to various input from you. This isn't a once and done process as your tank will always be changing and growing in many ways (good and bad at times).

Hope this helps some.

[blue_eyes53813]

The 3 main things to watch for a rise and fall in Ammonia, Nitrites and nitrates. The ammonia rises (any certain reading above 0) and falls to 0. Nitrites do the same and lastly nitrates... Ammonia and nitrites are the main thing. They are the most harmful to livestock.. Fish can tolerate low levels of nitrates.. If you are unsure if the tank cycled I wouldnt add any livestock for a few weeks. I would get some grocery store deli shrimp. Put it in a nylon and put it in the tank for a few weeks. This will kick the tank into a cycle for sure and than you can watch /monitor how your tank is gonna handle livestock waste. If you add livestock and the tank didnt cycle , it could kill them... The deli shrimp will also help the tanks beneficial bacteria as well.. Remember when you do add livestock to only add 1 fish every couple of weeks and monitor the water after each addition..

[Woodstock]

The average cycle time for a new tank with new/dead rock & sand is 4-6 weeks. They cycle is much shorter or even absent if you use live rock/sand that is fully cured. Fully cured rock/sand are populated already with the needed bacteria.

The nitrogen cycle is simply when ammonia (produced by rotting food, fish respiration, or by using raw ammonia) can be consumed by a special type of bacteria which produce nitrites as a byproduct. The nitrites are then consumed by another type of bacteria which produce nitrAtes as a byproduct. There is a final type of bacteria that will consume nitrAtes and produce a harmless byproduct of nitrogen gas bubbles.
The first two types of bacteria require large amounts of oxygen but the last type requires an oxygen-free area such as deep within live rock or within a deep sandbed.

Ammonia/nitrites will rise and then fall to zero. Once they are zero and you see the nitrAtes rising, your tank is considered 'cycled'. Ammonia and nitrItes are very harmful/deadly to livestock. NitrAtes can be controlled with water changes or a refugium stocked with nitrAte absorbing macro algae.

You can begin a 'cycle' by using a large cocktail shrimp from your local grocery store. This will eliminate the need to use live fish which could possibly die during the cycle.

[JT101]

Thanks for the replies. However, I am curious as to how long a tank has to exhibit a certain chemical balance before it can be "officially" deemed to be cycled. For example, suppose I am checking my levels every three days and I see that the ammonia is zero (which it has been at for a while now) but I see that the nitrate is hovering around at a certain level. OK, to make it easier to see my situation here is what I have seen on nitrates, by the numbers and by the dates (all readings are in ppm's of course):

6/15: 2.5 (this was taken about 5 hours after the introduction of all the LR, live sand etc).
6/17: 5.0
6/19: 5.0
6/21: 5.0
6/24: 5.0
6/28: 5.0
7/4: 2.5
7/9: 2.5
7/18: 5.0 (this was taken a few hours after I added some more livestock - sorry about that


Niitrites have been zero since the 6/28 reading.

Ammonia has been zero since the 7/4 reading.


Thanks
John

[blue_eyes53813]

Well it seems like (from your readings) the cycle may be about complete. Let the tank cycle through and than start small water changes. Dont stir the sand bed it hold the beneficial bacteria that is needed.

[JT101]

Originally Posted by blue_eyes53813

Well it seems like (from your readings) the cycle may be about complete. Have you done any small water changes? You could try a couple SMALL water changes 10-20%. To get the nitrates down. Do not stir the sand. The beneficial bacteria will be in the sandbed and you will suck it right back out.

Yes, I have done 10% water changes on 7/8 and 7/19. I have NOT stirred the sand but I have blown over the live rock with a SeaSquirt just prior to the water changes. I was going to do another 10 percenter on 7/29.

[blue_eyes53813]

Water changes During the cycle (ammonia and nitrites period) sometimes will slow the process.. It is great that you are getting into a routine of maintenance on your tank. You are doing a great job,, This may be very confusing to new hobbiest... During the cycle it is best to just let the tank be and let the bacteria build up. I dont think 10% will slow it down all that much but it may be enough to make the nitrates linger for awhile. I wouldnt worry about it.. But that is probably what you are seeing. I would waite it out till the nitrates fall. Actually I wouldnt do anymore water changes until the nitrates fall. let the tank finish.. it shouldnt take to long.. Than you can try to add one small fish, Monitor the readings for a week or so after the addition. Good luck

[Melanie]

Originally Posted by blue_eyes53813

I would get some grocery store deli shrimp. Put it in a nylon and put it in the tank for a few weeks. This will kick the tank into a cycle for sure and than you can watch /monitor how your tank is gonna handle livestock waste. If you add livestock and the tank didnt cycle , it could kill them... The deli shrimp will also help the tanks beneficial bacteria as well..

I think it was Lynn who suggested putting the shrimp in a tied up stocking if you are worried about a mess on the bottom of your tank.

[lcstorc]

Melanie you give me credit for everything. Nope that one was not my suggestion but it is a good one.

Follow the advice of Woodstock and Blue Eyes above. They have both given you great advice.

[JT101]

Please do not take this the wrong way folks, and I DO appreciate all the advice, but I am getting confused.

I posted another thread where I asked about water changes on a new tank, and I was told that I should be doing water changes already. Here, I am being told to NOT do water changes...

This is all so confusing....

[Woodstock]

IF the tank has completed its cycle (ammonia and nitrites at zero) then begin doing water changes.

IF the tank has NOT completed its cycle, do NOT do water changes as it will only slow down the cycling process.

[blue_eyes53813]

I am sorry John,, Just like Woodstock said... You can do small water changes during the cycle but it will slow it down.

It is alot easier and faster to let the tank go during the cycle, It can be done either way. Some people do and some people dont do water changes during the cycle.. The point is and why it may be taking your tank alittle longer is the tank is building up beneficial bacteria during the cycle by means of the die off on the live rock you added or some add die off(decaying matter with the deli shrimp). If you are removing the GOOD bacteria during the water changes( during the cycle) the tank has to rebuild that bacteria that you removed. You didnt do nothing wrong, Its just gonna take a little longer to cycle through. Once your tank gets enough bacteria to keep the tank clean and remove ammonia and nitrites ( fish waste mainly) you wont have to worry about it. Its important in a new tank to let it build and not take it out through to many water changes.

It can be very confusing and Im sorry to confuse you.

[JT101]

Ahhhh.....NOW it's much more clear !!

THANKS! I now see the light !!

I'll hold off on doing any more water changes and keep an eye on the levels and look for a drop in nitrates. Since the nitrites and ammonia have been unmeasurable for some time now, I think the nitrates will tell the big picture. Once I see that happen for a week or so then I'll feel better!

Thanks much again folks!

John

[JT101]

We were super-busy all weekend so I only had enough time, literally, to sneak in an ammonia, nitrite and nitrate check. This is what I found last night:

Ammonia: 0
Nitrites: 0
Nitrates: 10ppm!

I have not seen my nitrates this high since I started my tank. However, from what I read above, this is supposed to be good news, right? What I am worried about is how long do I have to wait until I see the nitrates go DOWN? I mean, is 10ppm a little high? It was hovering around 2.5 and 5 for a while, now it's higher than it has ever been BUT the ammonia and nitrites are zero, so I figured at least some of this is good...

Please help me out!

Thanks
John