Two Filter Cycling

[DaveP1991]

Here is an interesting one. We've come home today and found our small tank had sprung a significant leak and was in need or urgent replacement.

As such we dashed out and bought a new tank (we'd planned to anyway but just not now!), 50L replaced 28L. Obviously the fish have had to go straight into the new tank (3 balloon mollies, 2 glowlight tetra, 4 amano shrimp). I have taken the mature filter and therefore culture and set it to work in the new tank (along with the old heater and new setup) along with using as much of the old water as possible.

Clearly it is too small to do all the work for too long but I'm not adding any new fish for a while so hoping can support its current inhabitants. How long would people expect it to take for the new filter to get established?

I know this isn't ideal for anyone involved but there we go.

 

[daizeUK]

I would be tempted to put the old filter media inside the new filter and just run the new filter on its own, to encourage bacteria to colonise the new filter rather than stay in the old one.
 
The risk is that you may find your self in a mini-cycle because of lost bacteria which may have colonised the filter housing as well as any substrate/ornaments that did not get transferred to the new tank.  Keep a watch for ammonia or nitrite spikes and keep on top of regular water changes.

 

[DaveP1991]

Well I've transferred the few ornaments and two moss balls that were in the old tank so hope to have carried the bacteria from those across. 
 
I'll see what can be done with forcing the old sponge to fit in the new filter system! 

 

[the_lock_man]

I would be tempted to put the old filter media inside the new filter and just run the new filter on its own, to encourage bacteria to colonise the new filter rather than stay in the old one.
 
The risk is that you may find your self in a mini-cycle because of lost bacteria which may have colonised the filter housing as well as any substrate/ornaments that did not get transferred to the new tank.  Keep a watch for ammonia or nitrite spikes and keep on top of regular water changes.

 
Dave, don't just be tempted to follow this advice - just do it. This will be the quicker way of cycling the new filter. Daize is quite right, in that not all the bacteria will be on the sponges, ceramics, etc., but a very good proportion of it will be. Keep a close eye on the situation, regular water tests, and keep the ammonia and nitrite down, depending upon what your pH is.

 

[DaveP1991]

Well I've followed advice and here and shoehorned the old sponge into the new filter between the new filter media. Like I said there is about 20L of "old" water in the tank plus some plants, wood and ornaments from the old set up so I hope some of that will help. 
 
So far the current occupants all seem to be happy and healthy despite what they had to endure, including several hours in a coolbox...