Filter Replacement Question

[IndySE]

Hallo,
 
As per a previous topic I had I'm looking to rescape my tank soonish. I've got a Fluval Roma 200 and am currently running a U3 and a U4 filter in tandem. I want to get an external filter prior to the tank work and have my eye on a Fluval G3.
 
My question is, once I get the G3 how long should I have all three running in tandem before switching over to just the G3?
 
Cheers,
Indy

 

[CezzaXV]

Ideally, you should remove all of the media from the two you currently have, and stuff it into the G3 if possible. Then you can stop running your first two immediately. It's the media that's cycled, not the actual filter itself.

 

[IndySE]

I've read that the G3 allows for any hard media to be placed in it so that could be an idea, open the two hard media canisters in the U3 and U4 and use those.
 
If that doesn't end up being an option, what would I need to check to ensure the new filter has been cycled enough? Standard nitrate/nitrite/ammonia water tests?
 
Cheers,
Indy

 

[CezzaXV]

The bacteria should, in theory, spread themselves evenly between the available filters. If you were to remove one of your filters now, you'd be removing half the bacteria, and half the ammonia processing capability. The good news is that in a mature filter the bacteria should be able to reproduce quite quickly and get themselves back up to the numbers they were, but the best thing to do is to transfer as much media as possible from your U3 and U4 into your new G4. The more media you transfer into your new filter from your current ones, the less chance there is of being any problems.

Whatever you do, you'll need to monitor your ammonia/nitrite levels for a few days afterwards, just to make sure everything is as it should be.

 

[IndySE]

Update: I gave in and bought the G3 today! Took about 45 minutes to set up, really clear instructions and dead straightforward to do.
 
I chickened out with taking out the existing filters so have all 3 going at once, some if the fish are loving getting pushed around by the new flow, almost looks like they are on a rollercoaster
 
I was advised by the LFS to leave all three running for a month before turning the existing ones off, I think I'll stick with that plan, have always been extra caution as this is my first stab at tropical fishkeeping.
 
One other question I have is that is there a recommended way to keep a backup filter? I'll probably sell the U3 and keep the U4 in case of any issues with the G3 but is there a way of keeping it locked away somewhere so that I can just pop it in when I need to use it?
 
Cheers,
Indy