Cycles after upgrading tanks

Question
Hi. I recently upgraded from a 20g to a 30g aquarium and i was wondering if the new one has to cycle. Almost all of the 20 gallons of water from the old tank made it into the new one and i kept the same filter and decorations as well as the eight fish. Also i have been using the product Cycle. If it does have to cycle then will the time be reduced because of the old water and decorations being transferred. My second question regards my old 20 gallon. I set this one up today so i was wondering about the cycle times for it. All of the gravel that was used in it for 2 years is still there and the last inch of water remained but i filled up the rest with new water. Again i am using the product Cycle. If i kept all of the gravel which was never allowed to dry then do i still have to wait for a cycle period for this tank? I would really appreciate any insight you can give me as i don't want my eight original fish (all i have had for two years) to die in the new 30g and i want to start a guppy tank with the old 20g.

Answer
Hi Dave,

As long as you have the same filter in the 30g from the old tank, you do not need to cycle. It would be exactly as if the new tank was established just as long as your old one. You can put the eight fish in there without any problems. This is because all of the beneficial 'cycling' bacteria that remove toxins live in the filter itself.

I use Hagen's Cycle as well, and it's a great product. Your 20g still needs cycling, because there isn't much beneficial bacteria living in the gravel, unless you use an ancient under gravel filtration system. You can put new fish into the 20 gallon right away though, because you have Cycle combined with the old gravel.

Basically, as long as you use Cycle and perform regular water changes (10-25%) weekly, you do NOT have to wait for a cycling or 'break-in' period. The Nitrogen cycle is already present.

Good Luck, and Best Wishes to you and your fish!