Filter Sponge Change

[Ardvark]

I have a Interpet PF filter. Instructions say I need to change the sponge filters every two months. One is a carbon black filter and the other is a white filter. My question to members is this.  Will the changing of these sponge filters compromise the good bacteria built up in my tank OR will the good bacteria have enough numbers in the granules at the bottom of the filter?
 
                                                                                                       Al

 

[Ch4rlie]

Very rarely does sponge media need to be changed, this is more of an advertising gimmick from manufacturers to get you to buy more of their products.
 
During tank maintenance the sponge media only needs to be cleaned if its full of gunk and slowing water flow down from filter. And just a little squeeze in old tank water will do the trick, do not try to clean the sponge completely, you may be unwittingly getting rid of bacteria. And I do no clean ALL of the sponge media in one go, only about half.
 
Generally sponge media only needs to be changed if it is literally falling apart.
 
As for canon, this is only active for a few weeks, then thereafter is pretty much useless, it will no longer get rid of metals or meds from tank water. 
 
I only use carbon if am finished doing medication on my stocking. 
 
That means, I usually do not have carbon media in my filter, I fill in the gap vacated by carbon media with more sponge media.

 

[Ardvark]

Now I'm worried. During my weekly water change I've changed both sponge filters. How long will the good bacteria last for out of water and in the bin outside? What I'm asking is would it do more harm than good to put the old sponges back?

 

[ShinySideUp]

How long have they been out of the tank? Are they still wet?
 
As Ch4rlie says, sponge media only needs changing when it starts to fall apart and that might be years. Dump the carbon sponge filter and replace it with another ordinary sponge filter.

 

[Ardvark]

What's the story behind the carbon filter?

 

[ShinySideUp]

Carbon is put in the tank to remove smells, colours in the water (e.g. caused by new wood) and medications; it also has the effect of 'polishing' the water, i.e. making it crystal clear. However to be able to continue with these processes it has to be renewed every few weeks as it loses it's effectiveness, more than that, it is said that left too long in the tank it will start to release toxins back into the water although I can't prove this. Carbon will remove any liquid plant food you put in.
 
Many people substitute the carbon filter with another piece of sponge or other media, it's cheaper and more effective as a bacteria laden filter as it doesn't need changing, just a quick squeeze out in old tank water on occasions. If you really want to 'polish' your water then Purigen will do the trick although it is quite expensive and in my experience doesn't work for any near as long as the manufacturers say it will.