Prefilter sponge

Started looking into a prefilter sponge for added mehanical and biological filtration. Are they worth it? How much does it impede volume on a HOB?

 

I have a aquacleaer sponge cut to size and put over my intake on my canister filter. I did it because I had a mystery snail killed on the intake so it is a safety feature more than a filtering feature for me. When it is clean I don't notice it reducing my flow rate at all but I do have to rinse it in tank water about twice a week to keep it from slowing the flow down.

A tip if you do use one...when it comes time to rinse it off I put a cup up over mine and pull it off the filter intake with the cup over it...if I don't do that and just pull it off goes floating everywhere and it makes a mess.

 

I use a fluval prefilter sponge on my aquaclear but I don't count on it for biological filtration. I rinse it every week in tap water to get it good and clean. It keeps the mess out of my other sponges and protects my tiny fish.

 

I use a prefilter sponge on my RCS tank, for obvious reasons.

I have some nasty small plantlets that get sucked onto it and do impede flow, however, if I change out the sponge every week or so, I end up with good flow, safe intake, and actually, when I rinse out the sponge, it really does have lots of residue on it. So, overall, I think it's a good choice to have one.

 

A tip if you do use one...when it comes time to rinse it off I put a cup up over mine and pull it off the filter intake with the cup over it...if I don't do that and just pull it off goes floating everywhere and it makes a mess.

Good advice! I try to clean it up a little with the siphon hose before pulling it off but this is a good idea as well. In regard to flow slowing as above posters have said, only if it get really nasty.