Cycling a new tank with mature filter

[MattP]

Hi there, I'm setting up a 60l tank and have matured a sponge filter in my main tank over the last month or so. My question is what is the best way to introduce the filter to the new tank and what steps should I take to maintain the good bacteria which will have built up? Also any idea how long the tank will take to fully cycle if anyone has done this before?

Cheers Matt

[Industrial]

Depending on your tank setup, usually the sponge filter has enough bacteria to bypass a new cycle. In a bare tank, almost all of your bacteria will build up on the sponge filter, but in a heavily decorated tank, with a buried sponge filter, there will be less bacteria on the filter and there will be bacteria in the gravel and decorations as well.

I have never had problems moving an established sponge filter into a new tank with new fish. On the other hand, I always start light. Usually no more than 5 small fish in a 10 gallon tank. I usually try to do everything week by week in the beginning and that seems to work fine for me.

I have however, squeezed out a sponge filter, and tried to absorb the liquid into a new sponge filter and used that one in a small tank to breed fish and that failed, and the tank went into a shortened cycle and killed the fish (new and sensitive neons).

A good way to tell if the filter is still alive, is to get a small whiff of it, and it should smell earthy. If it does, then it is working great and will be enough to start a new tank! This method has never failed me.

[MattP]

Should I introduce the filter and fish simultaneously or one before the other.

Cheers Matt

[2wheelsx2]

As long as the water is dechlorinated and of the appropriate temperature range for the fish, it makes no difference. Even though the fish continuously produce ammonia, it'll take some time to build up, and once you introduce the filter, the bacteria will be right at work just like in the mature tank.