Pre filter on FX6 - reduced flow

[Galactik]

Hi

I just added a pre filter sponge on my FX6 to add even more bio filtration and easier maintenance but I noticed that the sponge has reduced the flow significantly.

Could this potentially hurt the pump on this filter or just reduce the flow with no mechanical issues?

I don't mind the reduced flow as I don't really need that much current anyway but wanted to see if anyone else has done the same on a canister this size.

The sponge i put in has big open cells so it should not clog too bad in a week maybe?( 80 gal hi flow sponge)

 

[dr exum]

Nice idea! I’d be curious too!

 

[Zack cloutier]

The fx6 and fx4 have variable flow valves on top of the canister so I would imagine if you have them set on max flow and the sponge slows it down a bit I can’t imagine it being an issue? I’m only about 75% confident in my own answer lol I could be very wrong. I have 2 fx4s one has been running max flow for well over a year with no issues. The other I have set to maybe 1/3 of the max flow on a 55g planted tank but it has not Ben running very long. If this is bad for the pump hopefully somebody with a bit more knowledge speaks up haha. Hope I’m not destroying my own filter

 

[Galantspeedz]

tried before. it clogs very easily. also reduced current is as good as reduced flow. reduced flow means water turnover is lower.

don't think pump will spoil though

 

[Raka]

The fx6 and fx4 have variable flow valves on top of the canister so I would imagine if you have them set on max flow and the sponge slows it down a bit I can’t imagine it being an issue? I’m only about 75% confident in my own answer lol I could be very wrong. I have 2 fx4s one has been running max flow for well over a year with no issues. The other I have set to maybe 1/3 of the max flow on a 55g planted tank but it has not Ben running very long. If this is bad for the pump hopefully somebody with a bit more knowledge speaks up haha. Hope I’m not destroying my own filter

Manufacturer recommends not to run more than 50% reduced.

 

[Raka]

Hi

I just added a pre filter sponge on my FX6 to add even more bio filtration and easier maintenance but I noticed that the sponge has reduced the flow significantly.

Could this potentially hurt the pump on this filter or just reduce the flow with no mechanical issues?

I don't mind the reduced flow as I don't really need that much current anyway but wanted to see if anyone else has done the same on a canister this size.

The sponge i put in has big open cells so it should not clog too bad in a week maybe?( 80 gal hi flow sponge)

View attachment 1393927

Tried this as well on my 206 and 306 as well as 70's. Didnt ever pan out I was cleaning the prefilter every couple day instead of weekly filter maintenance. I ended up adding another filter to accommodate the bioload addition I was looking for, which for you could be as simple as plugging that air line into a stand alone filter.

That being said depending on your setup if the lines are long enough to and from the FX6 with low enough flow you may see some denitrification benefits if you have achieved and anoxic environment.

 

[FJB]

Don't know the answer to your question.
However, I use prefilters on my two FX6 filters. I use a simple wrapping of plastic screen mesh, held by 2 rubber bands around the intake. I wash them every week, during water changes. Been doing it for years. I have not noticed almost any flow reduction, or very little. May want to try it. I also use the same (wrapped differently) with my AC110 and AC200 filters, as well as with a Penguin 350B. Cheap, nice dark color, easy to put on and off for washing.
Good luck.

 

[Backfromthedead]

Problem with those type of sponges is they'll clog easily under the pressurized drain of the can. The drain will tend to suck 90% of the water through the top 10% of the filter, thoroughly mucking up that portion constantly. Those sponges always seem to work better with air pumps that can create a nice uniform uplift through the sponge.

The most successful versions of a can prefilter ive seen on here used a long 10-12" diy intake pipe, perforated with holes its entire length, with a thinner wrap of sponge around it. Afaik all the thicker media like sponge in the can itself was removed and replaced with more bio media.