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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
 
#2 ·
That does seem awfully low. My 306 has much more flow than than and it has two outputs run through hydor heaters and one of the outputs exits through and fb300 sand filter. And all of this with a a sponge on the intake to act as a prefilter so that I don't have to break down and clean the 306 as often.

Has it always been this low or did it deteriorate over time?
 
#7 ·
Has it always been this low or did it deteriorate over time?
I clean the filter every two months. The flow seemed less recently so I switched to the "bio" sponge Fluval packs with these - Could it be the "bio" sponge? It should cause less restriction.

The Aquastop is fully open and the filter's output goes through a Hydor heater and a inline Atomic CO2 diffuser - both of which are ceramic tubes, it's a straight shot with no change in tube diameter. I recently swapped out the CO2 diffuser with a duplicate (I clean one and swap when they get dirty).

Do you have any kinks with your hoses? Aquastop valve fully open? Any obstruction in your hoses?
Nope, not a kink - there is about 3' of head between the top of the filter and the tank edge.

Dang! That sorta looks like the flow coming from the little HOB filter I have lol.
My Aquaclear 50 passed more water than this... I know the turn over is not as important with canister filters but this isn't sufficient.

Looks like the flow of my 405 lol. After neglecting my filter with maintance... I figured the impeller and motor took a hit. Waiting for boxing day sales to buy a new filter!

Maybe yours has the same problem but premature detoriation.
Yeah, maybe the motor is dying but after 9 months? I clean it every 2 months. The trays are filled fully with Matrix, more than the stingy amount of bio rings that Fluval sends with the unit - but It seemed stronger when I first got the filter.

video isnt playing for me just says unavalible;/, so first thing first. i would put my $ that the seal that goes around the impeller isnt seated all the way its kinda hard to push and you will hear a click to know its in for sure if not its quite possible that your filter is pushing the water out an back into the filter housing.

ill look back if i can get the video to play an give you better info of what i think.
ok well after watching it few ?s not answered. are u using filter floss or any small micron filter? and how much debris are in the filter after 1week? if you did a rescape or made a mess in the water colum it would cause this, so first take it apart an inspect it! if there is debris then its the filter doing its job if not your likely running into a clog or improper seat on the intake or impeller issue unless your using alot of fine micron polishing that can really slow the unit down. after that report back with all info fixed or unfixed issues an advice can go from there.
I wonder why the video wasn't available - i checked and it looks like it played - Thanks for the insite on the impeller seal - I'll check that tomorrow. I remember how hard you have to press it to seal.

there are two filter floss pads that do fine polishing at the top of the filter column - Fluval provides these and I replace them every 2 months with service http://www.amazon.com/Fluval-Filter-Water-Polishing-Models/dp/B001D070N6
I'll check to see if there is detritus in the filter when I check the seal - It had some when I removed the Purigen packs to start medicating the water last weekend.

One more thing - I used the awful Fluval corrugated tube for my intake - could it have gotten gummed up? Do you guys ever have to clean the tubes on the canister filter?
 
#6 · (Edited)
video isnt playing for me just says unavalible;/, so first thing first. i would put my $ that the seal that goes around the impeller isnt seated all the way its kinda hard to push and you will hear a click to know its in for sure if not its quite possible that your filter is pushing the water out an back into the filter housing.

ill look back if i can get the video to play an give you better info of what i think.
ok well after watching it few ?s not answered. are u using filter floss or any small micron filter? and how much debris are in the filter after 1week? if you did a rescape or made a mess in the water colum it would cause this, so first take it apart an inspect it! if there is debris then its the filter doing its job if not your likely running into a clog or improper seat on the intake or impeller issue unless your using alot of fine micron polishing that can really slow the unit down. after that report back with all info fixed or unfixed issues an advice can go from there.
 
#8 ·
no i havent had to clean the tube ever not your issue. sounds like you got alot of things slowing the flow, but its hard to say if everything is seated then sounds like u got to much crap heater co2 floss slowing it down, if its clean and everything. i dont even buy more floss its really not needed unless you got horrible water getting though
 
#9 ·
Id say test it "scientifically" if you can... Basically disconnect the filter from everything else, heater, co2, etc... and run it, see if that has dramatic improvement. if not, then take media out, and just run it empty, no attachments, and see if it looks right. If not then it's likely your pump, if it does improve dramatically, start hooking stuff up and filling it back up piece by piece with tests in between, it will diagnose what causes the issue.

Just my $.02

-Scott
 
#10 ·
Hey guys, I appreciate the tips!

Well, I tore it apart, there were almost no particles - no leaves, etc in the filter - the sponges were spotless. There was quite a bit of sludge at the bottom of the canister - though, I think that's part of the nitrogen cycle.

The impeller cover was on tight, they were both spotless.

The inline heater and diffuser are clean ceramic tubes, both the same size as the filter tubes, I checked - it would be like adding a few inches of additional tubing.

The tubing is clear with a few spots - the filter was bought and setup in March.

Possible issues: The media? Am I putting too much Matrix - Fluval is stingy with the Bio ring it provides - I have way more Matrix and it's a lot more tightly packed?

I am considering buying new 2217 or CFS-500 or an Aquatop if this is the case with Fluval filters after 9 months :(

Here's the flow after cleaning:

http://youtu.be/2YtFLlGpCFM


Here are a few pics:









Additional pictures in the album
 
#18 ·
Hey guys, Thank for all the suggestions!

1. I've set it up exactly the way the instructions say except I use purigen packs where the carbon goes and I'm substituting the Matrix for the bio rings. I think there may be too much matrix since it's a lot closer packed in than the 10 bio rings Fluval gives you(I hope that makes sense)

2. I'll use a 5G bucket and test with and without media...



Didn't think of that but I have small fish - I checked it and it's clean - I'm running the stock one so it shouldn't be an issue - I also took out the little ball that sits inside to help with the flow.

Check the white internal prefilter sponges, when my 206 slowed down they were the culprit. Crap seems to really build up in them and I found them hard to effectively clean.
Are you using after market pads on the top tray? If so some after market pads doesn't fit right and a tad bit smaller And it gets sucked up on the hole on the tray cover ,,,try putting the bio max on the top tray.
I was using two (one before and one after the purigen) - they were filthy with black sludge. I cleaned them out but I think I may just remove them all together because it was ridiculously clogged. It's almost as if the first sponge isn't catching anything - I honestly think this filter design is flawed with a lot of bypass - Do you guys have a lot of black sludge in your filters?

Definitely clean, clean and reclean or just replace those white tall sponges in the red tray, I didn't see the photo before but I bet that's your problem.
It's funny you mention those - they were spotless! Literally, just wet!
For the first sponge in the filter they were too clean considering the rest of the fine sponges were so thick with sludge. This is why I think there is a lot of bypass happening - The second reason I'm considering another brand.
 
#14 · (Edited)
ok if your not getting much diff in flow now then it sounds like to much packed into the filter. test it by removing the polishing pad and possibly some media, but if you have sludge sitting in the bottom that isnt good an makes me belive your sponges are not cleaned enough. from my experiance the coarser ones *tall ones* might need a bit of waterpressure to really get some of the gunk out then the sponges in the tray are fine and mostly catch silt. ill see if i can get a vid for a reference of my 406 for ya to see the water flow.

https://www.youtube.com/watch?v=orb95EY9Fjs
alright i did a video of my fully cleaned 406 with full media but no polishing pad. as others have said id do the test with a 3g or 5g bucket and time it then multiply to an hour and see what your gph is, it will vary with each tank with polishingpads,heaters,head height, etc. but i bet your right in line with where mine is. i took of the nossle to show u in the video as your lilys do basicly the same as it without the nossle*no build up of pressure to force water* just nice gentle flow. do the test with a bucket first an let us know where ur at.

hope it hleps ya
 
#17 ·
okay okay okay.....

ur setup...hmm...IMO not so good.. I know you can do anything to a canister ..but if you don't know what to use..it will clogg and prevent water flow...

Mine 205 is strong as hell and I have it up to the lowest setting (lever)..

my setup...starting from the bottom up

1. Lots of fluval prefilter (to get all the debris and large particlue trap first..i full almost max)
2. middle one...fuval bio ball with matrix (half and half)
3. top: matrix fill good enought to have room for the fine filter ..fine filter sits ontop fo the blue holder ( I cut my own fine filter)


my last cleaning was on 7/10/12...yes i write down when i clean it because i can go even longer...its might be due in spring or next year
 
#20 · (Edited)
Tested after cleaning

5G bucket test:

Without media - 1:44 seconds to fill (to the internal line) = 173 GPH

With media (Biofoam, 2 trays of Matrix, polishing pads) - 1:53seconds to fill = 159 GPH

The bucket edge was about 6 below the position of the filter output on the tank so the tank numbers will be a little less.

I should have done the test before I cleaned :)

I'll am going to do this again in a few weeks when it's dirty and I add the Purigen packs back... Ugh
 
#25 ·
Bent plate causing low flow.

I may have just stumbled upon the cause of your woes. My 406 was suffering from similar problems. Whilst cleaning earlier to day, I noticed that the plastic impeller cover was warped into a U shape. I immersed the cover in some freshly boiled water to soften the plastic, then bent it back into roughly the correct shape. (Slightly over doing it so as it would sit tight when back in position.) and then run it under a cold tap to harden the plastic again. Instant improvement. I hope that this is helpfully to you.
 
#26 ·
I may have just stumbled upon the cause of your woes. My 406 was suffering from similar problems. Whilst cleaning earlier to day, I noticed that the plastic impeller cover was warped into a U shape. I immersed the cover in some freshly boiled water to soften the plastic, then bent it back into roughly the correct shape. (Slightly over doing it so as it would sit tight when back in position.) and then run it under a cold tap to harden the plastic again. Instant improvement. I hope that this is helpfully to you.
Thanks! I'll take a look at that when I put the purgen back in the filter. Do you know what causes it?
 
#27 ·
Bent impeller cover.

Possibly might be down to the filter running too hot. Low flow due to long a period between cleans causing motor to run hot. Tank getting too hot during summer. Maybe the cover just isn't man enough for the job. By the way when you put the cover in the hot water hold it by the clip so as this part of the cover does not get hot. 20 to 30 seconds in the hot water is all you need to soften the plastic.
 
#29 ·
Glad I saw this. My 306 is having similar issues. On my 75 I have the 306 and a 305. The 305 (and my 405 in another tank have very strong flow) but the 306 is weak like in your video. I cleaned everything aka took my garden hose to it, and the flow did not improve at all. So a few days later I took out all my floss and those polishing pads out. The only media in it is the ceramic rings and those tall pre filter pads......and still a pitiful flow. So should I take the pre filter pads out?

Edit: Oh the 306 is only 6 months old. While the 305 I have had up and running for probably 6 years.
 
#35 · (Edited)
Found this one.

http://www.fluvalparts.com/servlet/the-915/well-cover-306-406/Detail

Bit cheaper at $9.99.

Haven't found one on this side of the pond yet.

Think I'll stick with the Ehiem idea.

Still, happy to of been of help.

Now don't think that it has anything to do with overheating. my tank certainly has not overheated in the last week. Just not man enough for the job.

Have just complained to Hagen in fairly short manner. sent them a link to this thread and expressed my displeasure at having to replace my filter after only 9 months. Will keep you posted.
 
#36 · (Edited)
Have just complained to Hagen in fairly short manner. sent them a link to this thread and expressed my displeasure at having to replace my filter after only 9 months. Will keep you posted.
I was looking at one of these as well (actually, a 306) but am rethinking the purchase if the cover constantly deforms and reduces flow as a result. Please let us know what you hear back from Hagen and good luck.
 
#37 ·
$2 @ PetSmart ($3 for other models)
I got a 404 from my uncle several years ago and the filter has been sitting in my garage. Just found it again last night and was going through the parts list as I'm thinking of using it as a secondary filter.

If you check PetSmart, they have a bunch of Fluval replacement parts for ridiculously low prices, I wonder why...
 
#38 ·
Great link. These look to be parts for the 04 and 05 series, I wonder how many (if any) are common with the 06 lineup.
 
#39 ·
Well I bit the bullet today and went and brought a Ehiem Pro 3 600. Had to wait a week for the shop to get fresh stock after the Christmas/New year break. I like to buy from a shop rather than the net. If anything should go bandit it's so much easier to sort. Plus, of course, your local aquarium supplier needs your support and you need your local aquarium supplier.

Have heard nothing back from Hagen.

The conversation when I made my purchase went like this:

Shopkeeper: "what ho?"

Me: "Did you put a Pro 3 600 aside for me?"

"Certainty did Fella. That'll be 200 notes please. Are you sure you need a 600? What are you running now?"

"406. Had all sorts of problems. Have you had any experience of them?"

"Won't have *insert expletive of choice* Fluval in my shop. No end of aggro. Can't get any parts. when you can get parts they cost stupid money" (his words not mine).

"You have parts for this one?"

"Got a full range of parts in stock. You won't be needing them though. Not unless you manage to break something."

200 down. 1 filter up. Hay ho.

The parts situation in The States may be different. But over here they are rarer than rocking horse poo.

Will keep you posted.
 
#40 ·
Hahaha, congratulations! it's the reverse here in the states, and we have more Fluval/ Hagan than fish and very little Eheim in shops unless they are special order. I bought the Fluval in a LFS for the same reasons as you.

I'm still testing my theory of bypass and detritus making it back into the tank... Thus far it looks like it's working but I need to wait till I get to the two month time to service the filter. I've been doing 50%water changes every 3 days (for an unrelated reason) so I can't tell if it's the filter or the W/C.

Please keep me up on the 600.

Sent from my Nexus 7 using Tapatalk HD
 
#41 ·
Weird, I have a 406 on a 36 gallon bow, lots of flow, tons of surface movement, tank clears fast. Have trays packed with all the stock media, plus purigen and dish scrubbies. and I have a sponge prefilter!

I did try to use a lily pipe style outlet once, flow/movement dropped way off. Put the stock outlet back and saw immediate return to high flow (with mollies/platies nose into the current playing). Maybe these filters are not so tolerant of changes/additions to the outflow side
 
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