Switching from internal to external filtering

[justinhill]

I've just ordered a Fluval 207 external filter pump to replace the hopeless internal unit on my aquarium. Here's my question: what's the best procedure for migrating from one to the other, without risking de-cycling the tank? I don't really want to run both pumps at the same time; as it is I'll have to dial back the 207 a bit so it doesn't create a whirlpool in my 100L ish tank. It might be possible to cut up the filter sponges from the old pump and stuff them into one of the 207's baskets I suppose. Or am I over-thinking this and I should just swap them over and have done? There's plenty of substrate, bogwood and plants that must have beneficial bacteria stuck to them...

 

[Essjay]

The safest way is to persuade all the old media to fit inside the new filter. If the new oone has ceramic media, put the old media in the basket then fill any spaces with the ceramic media. After a couple of months you can start removing the old media and replacing it with new, a bit at a time.

Yes, there will be bacteria everywhere else in the tank, and the plants will also remove ammonia, but I use the 'better safe than sorry' methods.

 

[P J]

Hi Justin, The Fluval 207 is an excellent filter, I ran mine in parallel with an existing internal filter for two months to ensure the Fluval establishes an adequate biological capacity, it comes with a great compliment of filter media there’s no point taking it out and stuffing in some misfitting kit from an old filter. If you do have some space in the Fluval use something like a K1 filter media, ceramic rings are way down the list in terms of efficacy. You may even decide to leave in the existing filter, you can never have too much filtration. You can also add a nice compatible Fluval UVC filter to the 207 as well to manage bacteria in the water column. I run mine 24/7 although part day operation can be selected.

 

[Essjay]

It is a myth there cannot be too much filtration. If the tank has fish that need fast flowing water it is possible to over filter, but when there are fish from slow moving water, they need a gentle flow.
Since the Fluval 207 is rated for a tank twice the size of the one in question, it will probably have to have the flow rate turned down rather than run two filters together.

 

[Ichthys]

It is a myth there cannot be too much filtration. If the tank has fish that need fast flowing water it is possible to over filter, but when there are fish from slow moving water, they need a gentle flow.
Since the Fluval 207 is rated for a tank twice the size of the one in question, it will probably have to have the flow rate turned down rather than run two filters together.

You’re talking about too much flow, not too much filtration. You cannot have too much filtration, but you can have too much flow.

 

[justinhill]

Hi Justin, The Fluval 207 is an excellent filter, I ran mine in parallel with an existing internal filter for two months to ensure the Fluval establishes an adequate biological capacity, it comes with a great compliment of filter media there’s no point taking it out and stuffing in some misfitting kit from an old filter. If you do have some space in the Fluval use something like a K1 filter media, ceramic rings are way down the list in terms of efficacy. You may even decide to leave in the existing filter, you can never have too much filtration. You can also add a nice compatible Fluval UVC filter to the 207 as well to manage bacteria in the water column. I run mine 24/7 although part day operation can be selected.

Good suggestion - unfortunately I'd already fitted the 207 by the time I you posted this and I've discarded the old filter unit. I stuffed two of its sponges into the new unit, in with the ceramic tube things.

 

[justinhill]

It is a myth there cannot be too much filtration. If the tank has fish that need fast flowing water it is possible to over filter, but when there are fish from slow moving water, they need a gentle flow.
Since the Fluval 207 is rated for a tank twice the size of the one in question, it will probably have to have the flow rate turned down rather than run two filters together.

You’re talking about too much flow, not too much filtration. You cannot have too much filtration, but you can have too much flow.

I bought the 207 rather than the 107 because I wanted the higher filtration capacity (a reaction to having to clean out the old unit every 3 days), but was worried about flow. But then I noticed you can adjust flow rate on these things. In fact, the flow rate on this 207 doesn't seem as fast as I'd feared.

 

[justinhill]

For the record, I'll mention my first impressions of the Fluval 207. Installation was easy, but I thought the brackets that mount the hoses to the tank were cumbersome to fit and bulky. One of these days I may look into some alternative inlet/outlet apparatus.

It's noisier than I had hoped, but this is partly resonance in the under tank cabinet so I'll have to find some way to damp it.

The quick-disconnect system seems to work great and it's all solidly built. I'm running with the 'default' set of media that came with it but there's a bewildering range of media options to think about. Including the contents of the canister and the pipework, it uses about 6 litres.

I also replaced my heater (the old one was sort of built into the pump) with a Fluval E200, and replaced the hideous lights with a Fluval Aquasky (which allowed me to add another 5 litres) - so I'm an all-Fluval operation now and net water volume is up from 83 to 94 litres.

The E200 heater's built-in digital temperature gauge is fun, but it reads at least a degree low and lags behind actual temperature change by HOURS.

The Aquasky is basically wonderful - but I can't stop tweaking the settings.