20g long. Set up some time last week (can't remember exactly which day.) In my existing 10g tank I had a bag of media seeding (for about 6 months) specifically for the purpose of this fishless cycle.

I threw in the established bag of media into the new 20g filter along with a bag of BioSpira. Every day I have been testing the params:

ammo = 0
nitrIte = 0
nitrAte = 5-10

Really there has been no increase in the nitrAtes. I'd say it's been over 5 days since the tank has been set up.

Can the addition of established media into a new tank truly "cycle" the tank? Maybe.....I am not 100% certain, however. Yeah - I'm a bit antsy in getting the fish into their new home b/c the 10g is now sitting on a card table and the kids keep walking by and shaking it....not too fun for the fish!

I am wondering if I should be adding ammonia to see if the cycle has been established?? I don't want to transfer the fish prematurely....

I would add some ammonia if it were my tank. The way I am understanding what you have posted you will need to add ammonia to 'feed' the biobugs that convert it to nitrite which will 'feed' the ones that convert the nitrite to nitrate. If you don't keep your cycle going somehow it will die off.

Let me know if I misunderstood tho.

In a fishless cycle I performed, oh about 6 months or so ago, I did add ammonia to the tank to get the "bugs" all in order.

In this case, in addition to the brand new filter media, I have also added media that has been sitting in the established tank. This media is already cycled.

However, I don't know if the addition of cycled media to a brand new tank constitutes the completion of a fishless cycle.

Does that make sense?

If this was an experiment, I would add the fish to the new tank and see what happens...however I am not interested in "experimenting" w/the fish at this point...and for some reason something in the back of my head is telling me to add some ammo and see what happens. It would be the same as adding the fish. Except if the tank is truly not cycled, the fish would not have to needlessly suffer.

(I'm just chattin' away...dont' mind me!!)

Yeah, I will stick with my first post and say add the ammonia and test away. Good luck!

Yep, you need to add ammo to feed the biobugs. Make sure you measure how much you add in and then test the water to see how high of an ammonia reading you get. When I cycled my 20 gallon long, I added 3.5 tsp to start which gave me an ammonia reading of 4. I then added BioSpira but didn't have the advantage of established media like you do.

By day 6 the ammonia reading was 0, at which point I added 1.0 tsp. The next day the reading was again at 0. I added 1.5 tsp and 24 hours later there was just a trace amount of ammonia remaining. So for the rest of the cycle I added 1 or 1.5 tsp daily until nitrites were at 0.

Once the cycle was complete, I added 2 fish and they cycle held its own--no bumps in the cycle.

If I were you, I would probably start with 1-2 tsp and see what the biobugs do with it.

Congrats on the new tank and keep us posted!

(As far as whether adding cycled media to a tank constitutes the completion of a fishless cycle, I believe the answer is--that depends. If you add lots of cycled media to a 10 gallon tank and add one small fish, I would guess the media would easily handle that fish's waste. If you add a small amount of media to a 20 gallon tank and add 2-3 large fish, it may or may not convert all that waste. So, since you don't want to stress the fish, toss in some ammonia and see how well the biobugs convert it to ammonia to nitrites to nitrates.)

Alright - I added 6ml of ammo to get a reading of ~4.0.

We'll see what happens tomorrow. For some stupid reason I was thinking I was all set w/the established media bag....don't know where my brain has been!

(oh I know where it's been...it's been fried from too much chilo talk earlier in the year!!)

As I already posted, I added a good dose of ammo late yesterday. Less than 24 hrs later I am still getting a high ammo reading (~4.0), 0 nitrItes and 0 nitrAtes.

I am going to go on the assumption that I added a whole lot of ammo.....and I will check later tonight to see what happens...

However, I am wondering if I could have possibly killed the cycle established in the media bag taken from the 10g??

argh....

I'm trying to erase that ordeal from my memory!

What kind of numbers are you getting now? How long was the media in the tank before you added food/ammonia?

My ammo is dropping and my nitrItes are going up. So the cycle is still there. I must have added a huge dose of ammo b/c so far it is taking about 3 days for the ammo to be processed into the nitrIte.

(and you know how I hate this "slow" process!! )