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Let's talk about Fluval's "vertical pre-filters"...

Stykk

Seedling
Joined
19 Oct 2020
Messages
7
Location
New England
Let's take a minute to discuss the "vertical pre-filter" in Fluval's canister filters. Is it just me or do they make no sense at all?? If someone wants to enlighten me and tell me I'm wrong, please please do.

What am I talking about?

These things:

Bio-Foam-Max_EN.png


And here's a look at how they're installed in the filter:

Healthy-Water-Vertical_EN.png


Fast-Action_EZ_EN.jpg


It might not be easy to see here, but it's installed on one side of the filter chamber, and the water flows in through that little gap next to where the guy is pinching the red handle. What you don't see, when you look straight down into the filter chamber with everything installed is a pretty sizable gap between the wall of the filter and the blue foam. Fluval is telling us that the water will flow down through the vertical white and blue foam, then up through the gray baskets shown on the right in the second picture.

Sure, some water is going to flow through this foam, but I can imagine a lot is just going to flow right through the open space. It just seems like such a waste of space and a really poor design. Was Fluval just trying to be different and be able to point to something neat and say "look, vertical filter! bet you've never seen that before! buy me buy me!"? Or is there some actual benefit to this arrangement that I don't understand because I'm not a water flow expert guy?

Why am I asking these questions? Because I have a 207 and a 307 and I'm pretty disapointed in the performance of both. They do not seem to get the water clean, and I am pretty certain it comes down to the vertical pre-filter.
 

erwin123

Member
Joined
4 Mar 2021
Messages
200
Location
Singapore
I upgraded to Fluvals from Eheim Classics and Ecco Pro - super reliable but extremely dated designs.

My experience is that the pre-filter definitely traps various sorts of dirt and dead leaves (which could clog up finer filter media). When I clean the pre-filter, I find that I am removing a satisfying amount of gunk. In comparison the Eheim Ecco Pro 300's prefilter is much smaller and hardly picks up any dirt (its so coarse I think its only designed to stop large debris like dead leaves). Then there is the Eheim Classic which has no prefilter whatsoever and if you want to have a coarse prefilter pad, it is at the bottom of the canister so you have to remove all the media to clean it....

If your water is not crystal clear, isn't that the job of fine filter floss (or dare I say it... purigen?) rather than the pre-filter?
 

Kevin Eades

Member
Joined
24 Jan 2021
Messages
171
Location
Portsmouth
I upgraded to Fluvals from Eheim Classics and Ecco Pro - super reliable but extremely dated designs.

My experience is that the pre-filter definitely traps various sorts of dirt and dead leaves (which could clog up finer filter media). When I clean the pre-filter, I find that I am removing a satisfying amount of gunk. In comparison the Eheim Ecco Pro 300's prefilter is much smaller and hardly picks up any dirt (its so coarse I think its only designed to stop large debris like dead leaves). Then there is the Eheim Classic which has no prefilter whatsoever and if you want to have a coarse prefilter pad, it is at the bottom of the canister so you have to remove all the media to clean it....

If your water is not crystal clear, isn't that the job of fine filter floss (or dare I say it... purigen?) rather than the pre-filter?
I have the exact same experience with the pre filter picking out the large debris. And the odd shrimp that found its way in and wants to live in the filter. I add filter floss to the top basket to get crystal clear water but this needs changing regular as it clogs and blocks flowb
 

OllieTY

Seedling
Joined
20 Jul 2020
Messages
20
Location
Birmingham
It's only the same as a sump having some sort of 'reception' area before the water starts to flow through the sponges. There is no issue here. I have a 207 and am very happy with it's performance with a 100l tank.
 

John q

Member
Joined
6 Jan 2021
Messages
556
Location
Lancashire
07 gets the thumbs-up from me too. I run a 307 and a 407 and very rarely get any leaf, moss or other solid debris trapped in the black foam, it always gets trapped in the blue/white foams, which are cleaned weekly.

I used to use filter floss but found it restricted flow to much, now I only have the standard foams like above picture and one tray containing a small amount of ceramic rings, water clarity is good.
 

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