Replacing filter floss media


There is some filter floss I have from when I first begain cycling the tank on 8/30/2019. My tank Cycled around mid October. Now back to the filter floss It has all but stopped the flow of water out of the HOB into the tank. I have cleaned it in old tank water on water change days. That being said I know a significant portion of this bacteria lives in the filter. I have sponge material and biomax in the HOB compartment. If I have to get rid of the filter floss will it reset my cycle or cause a mini?


Whilst the floss will contain some bacteria most will be in your Sponge and biomax. Bacteria numbers can double in 24-48 hours so the remaining bacteria should replace any lost within a day or so. You could reduce load on the bacteria by not feeding the fish for a day after removing/ swapping the floss. The rule of thumb when replacing biological media is to change half at a time then wait at least a week before changing the other half, however as floss is mainly a mechanical media and you have other biological media you should be able to remove it all.
I would replace the floss with new rather than just removing it as it stops your foam being blocked by sediment. Without the floss you will need to clean the foam more often and as your foam is both mechanical and biological media cleaning even in tank water could reduce the bacteria held within it.


I have filter floss, sponge and bio-balls in my HOBs. I replace my filter floss for new ones every 2 weeks. You shouldn't have any issues.


If I am unable to rinse out the Polyfil I use, I just toss it and replace it in my Aquaclears.

In the canisters it always gets tossed and replaced.

I've never had an issue from doing this. Don't under estimate how much beneficial bacteria will colonize in the sponge foam. As long as you don't lose all the bacteria in the foam, then you will be good

Señor Pescado

I replace the filter floss and vigorously squeeze out the sponge in my HOB every time I do a filter cleaning, and I've never had any cycle issues. Sometimes, I'll put the new filter floss I'm going to use in the top portion of the filter a week before I perform the filter cleaning, so bacteria can colonize before it's in use.
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