Fishless Cycling two tanks... getting weird results.

BabyBoyBlue

10 Gallon tank, used to be my bare QT tank. I had a Platy and a Rasbora for about a week in the tank, them moved them to another tank. Didn't change the water afterward, left the filter running for 3 months with no fishes. The tank as far as I knew was not cycled.

Bought a 30 gallon tank brand new with new filter and decided to do a fishless cycle with both 30 gallon and 10 gallon tank on the same day.

Bought new substrate for both (Carbisea Instant Sand) and added Ace Ammonia to get 4 ppm on both tank.

3 days later, I check the ammonia on both tanks using API freshwater tube test.
10 gallon tank I read 0 ppm ammonia and 4 ppm nitrite.
30 gallon tank I read 5 ppm ammonia and 0 ppm nitrite.
I add another dose of ammonia to the 10 gallon tank to get 4 ppm of ammonia.
I add some media from another tank to the 30 gallon.

On the 4th day (today), I do another test.
10 gallon tank I read 0 ppm ammonia, 5 ppm nitrite, 20 ppm nitrate.
30 gallon tank I read 2 ppm ammonia, 2 ppm nitrite, 0 ppm nitrate.

Why is the 10 gallon tank cycling so much quicker?
Is it possible that leaving the fish waste for 3 months and leaving the filter on the cause why it is cycling faster?
There was only a little bit of fish waste as it was only 2 fishes, and it was only a day's worth of waste from those two fishes.

Tazman

Smaller volume of water and as such requires a lot less bacteria than the 30g to convert the ammonia.

Everything seems to be progressing normally with the results you have shown. The 30g tank is doing well considering you are using media from another tank.

Olympia

To achieve 4 parts per million in ten gallons of water is much less than in 30 gallons of water.
Explanation- if you had 4ppm, and you had 10 million parts (represents the 10 gal) you would have 4 x 10, so 40 parts ammonia.
4ppm in 30 million parts (30 gal tank) is 4 x 30, so 120 parts.
It takes less bacteria to eat 40 parts than 120 parts. :)

I agree- both tanks are progressing well.
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BabyBoyBlue

Sounds good. :)

Just wanted to be sure that I didn't mess something up. :)

Thanks again!

AbbeysDad

A couple of things come into play here. First, the 10g tank had the advantage of the bio-seed from the previous fish. Yes, the tank sat somewhat idle causing the bacteria to go into a stasis like suspended animation, but they sprung back to life as soon as ammonia was added. The 30 gallon was more 'virgin' and as others have mentioned, has 3 times the ammonia as the 10g to equal 4ppm (which would require 3 times the beneficial bacteria to process).

So your results seem normal. Be patient weed hopper and cycling will come

BabyBoyBlue

That makes sense. I was just surprised that it was going so fast. I thought it was going to take much longer. :)