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Fluval 406 with awful flow...

65K views 70 replies 25 participants last post by  Westone 
#1 · (Edited)
I've had an issue with constantly having debris on my plants and in my moss - even though I do a 50% water change weekly.

I usually agitate the plants to get the debris into the water column hoping the filter will suck them up... Well, not with my Fluval 406.

Background info:
My 406 was cleaned last week, impeller, media, and all - I've even removed the Seachem Purigen packs because I'm using medication this week. I have it set up with the "bio" sponge at the bottom, 2 trays to the brim with Seachem Matrix, finally 2 Purigen packs in the top tray. I had 3 trays of Seachem Matrix and switched the "bio" sponge in order to help flow, but it hasn't helped.

I've read that manufacturers rate filter GPH with no media, 1mm of head and a lot of praying, but this is ridiculous!

How does your Rena or 2217 measure up to the following video?

http://youtu.be/VpqQGSRannI
 
#44 ·
I've got lily pipes on my 306 and it flows out slow like that as well. I figure it was just the design of the pipe that made it appear like that. I also had switch back to the stock inlet because the filter was noticeably noisier with the lily pipe one. :icon_mad:
 
#46 ·
This morning I installed the the Ehiem.

First impressions: Build quality is if a VERY high standard. Design is by someone who knows what he's doing. Parts and filter media are designed to last, not be replaced. Oh and the impeller cover looks like it could hold in a port hole on a submarine.

I have plumbed it in using my existing Fluval hosing, which I found to be a good snug fit, I used the hose clip that came with the Ehiem to secure it to the hose connector of the filter. Looks good, will keep a close eye on it for a week or so in case of problems. My reasons for using the Fluval hosing are:
1. It is extremely flexible and will not kink.
2. The brackets that mount it to the side of the tank prevent the weight of the water filled hose from pulling fittings such as lily pipes out of position.
3. the only joints outside of the tank are where the pipes connect to the pump head. (reduced risk of leaks).
4. Its does not seem to get contaminated and clogged in the way that "standard" hoses do and so needs much less cleaning.
5. It has a larger bore than the Ehiem pipes and so should not cause any flow problems.
6. I wanted to be able to directly compare the output of the Ehiem to the Fluval.
7. The Ehiem hoses and fittings are green. No actually they are GREEN. (for the correct effect you need to SHOUT that last GREEN loudly, No louder than that. Louder!)

Flow is at least double that of the Fluval, possibly more. Of course it's all brand spanky new at the moment.

So how does it filter water?

First of all there is NO bypass. None, nada, zip.

Water enters the top of the filter and is drawn into the Bottom of the top tray, which is sealed off from the other 4 media trays, it then flows against gravity and though a coarse "pre filter" until it can flow down a triangular channel in the corner of the filter box, the opening of which is above the pre filter. (gravity trap, designed to take out any large/medium solids).

Once the water is at the bottom of the filter box it enters a void below the bottom media basket before being drawn very slowly, due to the large cross section of the media baskets, upward. (another gravity trap)

There are 4 media baskets. The bottom 2 are filled with "MECHpro", short sections of small gauge ribbed plastic tubing, designed to trap medium/small solids. These are completely reusable and washable. The third basket is filled with "bioMECH". Cramatic media designed to trap small solids and to provide some biological filtration. This is also washable. The last basket is filled with "SUBSTAT", a cramatic biological media, topped off with a large polishing pad. The biological media does not require replacement. It is recommended, by the instructions, that the polishing pad be replaced rather than cleaned. But you can clean it if you need to.

All in all I think that the Ehiem is going to work out much cheaper than the Fluval in the long term. (apart from the fact that it actually works)

Oh yes. it only does 16 Watts if electricity and no you can not hear it AT ALL.

So apart from the GREEN hosing and fittings.

Whats not to like?

:):):):)
 
#47 ·
I have a 406 as well and I was having flow problems, to the point there was almost none. I completely took the filter apart and cleaned as you have, still low flow. Then I found a similar post and discovered that the impellers on the fluval are very sensitive to wear. The blades on mine were just very slightly rounded on the corners. Replaced impeller, works great again.
 
#62 ·
Just an update.

I serviced the filter today, along with my 50% water change.

A lot of debris in the bottom of the filter. This is a good thing, I want it to capture this stuff.

I noticed something when putting it back together, there isn't really a path for the water to go from the long sponges to the bio sponge at the bottom of the stack. There is a plastic wall that rises from the floor to keep everything stacked but no clear path to allow the water to enter the bio sponge and move up the column of baskets.

Can someone check this on their 405/406? I may have missed holes or something but I think this is why there is bypass, the water just goes where there's least resistance.

I didn't heat and bend the impeller cover back, I just cleaned it - I also cleaned the place it sits in the filter head. It was a little wobbly, but I wanna see how well this works...

2:00 minutes to fill a 5 gallon bucket before cleaning
1:50 seconds to fill a 5 gallon bucket after cleaning

Previously I had: 1:41 seconds - 178 GPH.

I hypothesize the impeller cover warping has something to do with this.

Well - If I can't DIY fix the issues, I'm going to put this on CL and sell it and replace it as soon as I can afford another brand that performs better.
 
#63 ·
Hey Guys,

I just saw and read threw this thread, and I am very surprised to hear about the problems with the 406 filters! I have 1-204 and 2-205, and they are awesome!!! Very quiet, strong flow, easy to clean, so no complaints here!

One thing I see different between the 204/205 and the 406 is the impeller cover! The cover on the ones I have are very hard clear acrylic, and they snap on both sides of the cover. On the first sponges (the tall ones in the plastic tray) the directions show to leave 1 side of the sponges sticking up above the tray. If I remember correctly it is the rear set. That is what keeps the water from bypassing them, because when I leave them sticking up like the directions say, when I go to clean the filter the next month the sponges are smashed down where they have been pressed down by the motor housing. I am not sure if the 406 is designed the same way, so take this with a grain of salt!

I am not trying to start anything here at all, but just trying to see if I can help! I really do hope Fluval isn't going cheap on us, since I have had my 204 for 7+ years now and truly love it! All I have ever had to do other than clean it was to replace the impeller last year, and I replace the tall sponges once a year too! That is it! I would 4 sure email or call Fluval and try to figure out a fix to your solution!!! Most manufactures I have dealt with are more than happy to get things worked out with their customers, because in this day and age a unhappy customer can spread the word to A LOT of people and quickly too!

So anyway BEST OF LUCK in getting this thing fixed!
Drew
 
#64 ·
Hey Guys,

I just saw and read threw this thread, and I am very surprised to hear about the problems with the 406 filters! I have 1-204 and 2-205, and they are awesome!!! Very quiet, strong flow, easy to clean, so no complaints here!

So anyway BEST OF LUCK in getting this thing fixed!
Drew
Hey Drew,

Thanks for the suggestions. I just did the trick with the sponges when I serviced it this time. Let's see how that works between this service and the next one.

Does the impeller cover for the 20x series work with the 406?

Have you taken a look at the bottom of the canister to see if there's a channel for water to flow? It may be different on the 10x/20x series of filters.

Sent from my Nexus 7 using Tapatalk 2
 
#65 ·
Sundragon, how did this turn out in the end? I just bought and installed a 406, and I am not happy with it. The flow is fine, but there seems to be a lot of bypass. Its been running on my 90g for 4 days, and it is not clearing large particles from the water. I'm about to take it apart and see if there is any evidence of it filtering anything out, or anything installed incorrectly leading to bypass.
 
#66 ·
It's a POS. Never buying another Fluval product. I had their Aquaclear 50 HOB, which was wonderful and i thought the 406 would be good. The second hand Eheim I had bought broke last minute and I pretty much bought the Fluval on a whim. It is 1/2 the price I paid for it on Amazon fwiw. I've had to replace the main valve unit when it broke as I was trying to remove the tubes to swap the CO2 diffuser - if you're using injected CO2 with an inline diffuser, purchase another valve in case. I had to Fedex mine from Amazon (great service though).

Were I you, I would return it and purchase another brand. I'm considering something more powerful as this can't even keep the carpet clean of detritus the day I do a 50% water change and serviced the filter. It's really absurd.

I would get an Eheim or if you really like Fluval, the fx-6 (which is overkill for my 57G)

Sent from my iPhone using Tapatalk
 
#67 ·
Just a quick idea. Is it possible to put the Fluval top (motor unit) on backwards? On my Fluval the is some writing on the bottom portion that contains the sponges etc, and this writing continues on the top. That is how I know I have them together correctly but I have never tried to reverse the top. Perhaps you have reversed them and impeller is not over the opening in top tray? Flow would be greatly affected.
 
#68 ·
Haha, thanks, but it's on properly. The writing is visible. I don't even think one can attach it reverse. The impeller cover is probably not sealing but the overall design is flawed as water doesn't have a channel from intake to output like the Eheim Classic and FX which force the water through all the media. Judging by the detritus pattern on the inside, a good amount bypasses the media stack.
Lesson learned :)



Sent from my iPhone using Tapatalk
 
#71 ·
I have to agree. I'm glad many people have had a good experience with the 406. I read many positive reviews or I would not have bought one myself. I'm no engineer, but the design seems like a great one. Unfortunately, it's not cleaning the water in my tank. The flow is great, but after 5 days now there are still copious amounts of visible particles in the water.

I talked to the store where I bought mine today, and I'm returning it as soon as I get my Magnum back in service.
 
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