Tank cycled... what am I waiting for?

LX20000

New member
Howdy... I just set up an Innovation Marine 40 gallon about 11 days ago. Standard pump, MD10 power head, 20 lbs of sand, 35 lbs of live rock that was likely cured or near cured at dealer.

So I let the tank sit for week, then tested for the nitrogen cycle
Ammonia - 0
Nitrites -0
Nitrates - 20

So I got some 10% ammonia hydroxide from ACE, and dosed the tank to 1.5 ppm ammonia (about 2ml of 10% added).

Next day
Ammonia - 0
Nitrites - 2 to 3 ppm
Nitrates - about 25

Day after that, Nitrites are zero as well.... this was done on day 8.

So... I ask my dealer, when can I add something? He says, "Wait 10 more days so that you have waited a full three weeks for the tank to settle".

Humm... what am I waiting for? The bacteria must be there an working, right? So I can't be waiting for the bacteria to develop... and if there is no bio load on the tank, am I just "waiting" and letting the bacteria I have, to die off?

I got out of the hobby 15 years ago, when it was "Set you tank up, throw in live rock, and a damsel for every 10 gallons"... I understand this new approach of not stressing a fish, and not ending up with damsels you don't really want, but just "wait 10 more days for the tank to settle" leaves me wondering if this is just an old wives tale.

So, add some snails, crabs etc now, or wait for "something" for 10 more days, or can I even add a couple hearty fish now??
 
You're waiting for the biological filter to establish itself (but you know that). If you feel you have enough experience to judge the tank as cycled, then I would say to do as you choose. I've set up tanks using rock and sand from an existing tank (along with about 50% used water) and put fish in it the next day.
If you feel confident it's cycled then go ahead to plan b.
 
Sex among bacteria takes time, just as babies do. (except they grow fat, then divide) Add members of CUC slowly, over 4 weeks, while feeding tank; and you can start your first fish in TTM (see sticky).
 
Good... CUC was mentioned... another item I do not understand... there is nothing to clean up in my tank.... what would the CUC eat?
 
I wouldn't add more than a snail or two, maybe a shrimp if you want it. I added a cleaner pack to my tank after cycling, most just died.
 
Its not the easiest thing to do in this hobby but best to take things slow. If you have an idea of what fish you will be adding to the tank, start with a small inexpensive fish. I would throw in a few snails and hermits as there should be plenty of food on the live rock.
 
OH.. feed the tank, like put in frozen brine shrimp or something.... I assume a TEENIE TINY amount of it.... How about regular crabs?? I always like them...
 
Sex among bacteria takes time, just as babies do. (except they grow fat, then divide) Add members of CUC slowly, over 4 weeks, while feeding tank; and you can start your first fish in TTM (see sticky).

Sorry.. which sticky.. and what is "TTM" ??
 
Tank cycled... what am I waiting for?

If you got live rock that was in water shared with multitudes of strange fish, I would consider leaving it fallow for 76 days anyway to make sure you don't have any parasites that will cause problems later on with your fish. You only get one chance to QT your rock.:-)


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I went 2 months rock only.
Then added CUC.
2 months later added first fish.
4 months no fish boring.
That "something " you are "waiting" for is your tanks to stabilize a bit before adding fish.
By the way my Yellow Tang was my first fish, he is dieing. 12 years old.
 
The problem most people fall into is all they focus on is the initial cycling process and think okay that's over and it's safe to add whatever. Cycling is just the first step in a new aquarium and there are several other stages such as different types of algae and tank changes that occur over the next several months.

The bacteria overpopulate when cycling and then you'll have it go back down to normal levels or to what the current bioload is on the tank. If you don't even have enough algae I would skip a CUC for now cause it doesn't make sense to add them in my opinion. There is no guarantee you'll have enough algae and may take several weeks or months.

I know it sucks looking at an empty tank but patience will pay off. I added 1 fish 8 weeks after my cycle completed and my cycle completed in 2 weeks so 2 months before my first fish was in the tank. It was another 4 weeks before I added another fish. You need to slowly build the bacteria up according to the bioload and adding 3-4 fish will only hurt in the long run as the bacteria will have to adjust to the bioload again.

You can see tons of examples on this forum every day of people who think just because the tank cycled they can throw a bunch of livestock in and be okay. Once my tank cycled it was another month before I started to see a significant amount of algae which didn't last more than a couple weeks.

I personally think once you cycle the tank you should set up a QT tank and buy 1-2 fish and this will give you something to keep you a little busy and is a perfect time for a QT tank in my opinion.
 
I'm not trying to be a d--k or some sort. If you believe your tank is cycled, Your ready to add fish. Then I say do it, I think everyone has given you great opinions and knowledge. It's your tank to look at everyday and care for. Update us on the outcome
 
I'm not really in a hurry to do fish. Was just wondering when I can add a crab... or two...

I don't have any algae, because I am following what others have said, and proving the tank with limited light. So it seems I should not even add a crab, what would it eat? Should I light it more, do I want algae?

Also, I'm not trying to disagree with the "wait a month" school of thought. I am just trying to get a better understanding of the processes involved in "letting the tank settle". I tend to want to understand the underlying processes involved.
 
Next day
Ammonia - 0
Nitrites - 2 to 3 ppm
Nitrates - about 25

IMO the dealer gave you a lazy answer. If your nitrites were not to zero in 24 hours after dosing to 1.5ppm, then the tank does not have the necessary bacteria yet. My personal rule of thumb is when the tank converts all ammonia to nitrate within 24 hours you have established enough bacteria to begin to add livestock. There are a myriad of things to "settle" in our tanks and they do not do so in 10 days. Maybe not even 10 months. Nonetheless if water parameters are within range I would decide on your stocking list and put fish #1 on your buying list. How or if you choose to QT is not the point of this thread but rather what you are waiting for.

For a little "light" reading you might check out my post here for a little discussion on tank cycling. Also I would maybe use 2.0 PPM of ammonia as a test. I also think a small CUC could be added now and "fed" or later when you have algae and whatnot for them.

Incidentally what are your tank parameters now that it has been a couple of days?
 
I'm not trying to be a d--k or some sort. If you believe your tank is cycled, Your ready to add fish. Then I say do it, I think everyone has given you great opinions and knowledge. It's your tank to look at everyday and care for. Update us on the outcome

Just don't be dumb like me and add a couple fish that might be sensitive to even slight ammonia spikes. Start with something hardy that can handle the new tank's parameter swings and possible ammonia/nitrite/nitrate/random weirdness spikes. Like a crab or snail if that's what you want.
 
I dosed to 2ppm again last night. I was at 0/0/40 on the nitrogens.

24 hours later, 1ppm NH3, 3-4ppm Nitrates, 40ish on Nitrates.

PH at 7.9 with a calibrated PinPoint. Alk at 10.2. Have not measured Ca or Mg.

So I guess I am light on bacteria still.
 
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