Has my tank cycled? What's going on here?

Hi everyone.

Not entirely new to the hobby. I have one tank that's been up for 2 years now with no issues.

I just started a 90G tank (http://www.3reef.com/forums/show-off-your-fish-tanks/brews-90g-build-105491-5.html), and I'm a little confused as to what is going on with my cycle.

I added the base rock + dry sand on the 11th of this month. That same day, I seeded with 5 cups of sand from my established tank, as well as probably 15lbs or so live rock. I also added 2 dinner shrimp which I left decaying the 80 degree water for about 2 weeks..

I haven't been very good about checking my water chemistry this whole time. I checked about on the 23rd, and the values were as follows;

Ammonia; 0.25
Nitrates; 15
Nitrites; 0.25

Today, (29th, which is almost 3 weeks since seeding + shrimp rotting) and my values are allllllll 0's;

Ammonia; 0
Nitrates; 0
Nitrites; 0
I'm not planning on adding any fish for another two weeks. (my t5 comes in this Wednesday). I'll get a CUC in there a week after the light (hopefully they'll have some algae to eat).

I guess I'm just confused as to how or if it has cycled this fast?

I haven't done any major water changes (I added about 10 gallons to the sump about 5 days ago, but that's it.)

Any thoughts?

 

The live rock may have not have had any die off and this allowed it to seed and handle the ammonia from the shrimp. Tests may have gone bad. Did you add anything like Prime to the water added to the sump?

 

Your cycled IMO.

You just missed the largest ammonia value.

You can test whether cycled by adding a small amount of ammonia and see how fast the system converts it to nitrates if you are still concerned.

The only thing that really sticks out at me is that the value for nitrates is 0.

If it were my tank I would add some fish food, test again in a day or 2 see where the levels are at and proceed from there.

 

The first idea seems plausible... but they were 2 HUGE rotting shrimp. lol
Tests... ahhh, slight possiblilty, but I checked with a test kit that is 6 months old, and one that is older. I hate buying new test kits from the LFS... they're like 10x the price they are online.

I did not add anything to the water, other than reefcrystals. I'm a big proponent of allowing the tank to cycle naturally.

I guess what I'll do is wait for the light to get here on Wed. If nothing has changed by then, I'll take some water to the LFS and have them test it for me. If they get the same readings I do, I'll pick up some hermits and snails to get things going.

 

As I said in my last response, I do have some time to kill before the lights get here.

Maybe I'll put another small piece of shrimp in there and check the water daily to see what happens?

 

I agree with whats been said so far, you might be cycled already. But I would definitely not take any chances. Add some food or shrimp and watch closely this time.

 

your plan to add some of the CUC 1st sounds good to me Brew

provided they behave as they should for a week or 2, your good to go with 1st fish IME

Steve