Cleaning External Canister Filters

[wombat1100]

Hi guys, I was wondering how often you people clean your canister filters, I do mine about every 2 months, they seem really dirty by then but i am hesitent to clean them more often so as not to disturb the bacteria too often.
What about you guys?
Daz

[joz]

Thats fine,aslong as you don't use hot water!Generally I use a bucket of tank water for the medium.Then rinse the cannister under tap water.

[Sloory]

Yeah i'd say that mine are done every two months also.

[GoGuppy]

Yeah i'd say that mine are done every two months also.[/b]


G'day Dazz

As mentioned in my introduction posting, I used to clean my external fluval cannister elements almost weekly, and at the same time experiment with different media. A friend at work who also had a FT pointed out to me that this was far too often and that he only cleaned his once a year, or there abouts.

I have now also dramatically cut back to probably less than once a year, but this was only possible after I removed the fine grade medium I was using. Together with a pH of around 6.6 to 6.8 I do not detect any nitrites (or nitrates for that matter) in the water.

One thing I have done, based on my experience on general industrial pumping and filtation, is to install a back-flush system. As this has worked well for me, and I have not seen a commercially available system in the shops that does the same thing, I&#39;ll briefly explain the system I use. << Sorry, I tried to be brief but it&#39;s hard to describe even simple actions in detail, It is not really as complicated as it appears below ;) >>

The back-flush system basically comprises placing a Tee-piece in the line from the tank to the filter inlet, with the Tee located between the inlet shut-off valve and the filter.

Connect a line (with a shut-off valve at the other end) to the centre leg of the tee-piece. I also have a valve at the outlet of the filter, which of course is fairly standard for maintenance purposes. The discharge (return) line from the filter should terminate at about 100mm below the normal waterlevel in the tank. The tee-pice and the third line should both be the same size as the line between the tank and the filter. I use clips to ensure they don&#39;t disconnect.

Now, to back-flush the filter, mainly to get rid of larger debris and rubbish in the bottom of the cannister, I switch off the filter and close the filter inlet valve. Do not do this with the pump switched on as it will cavitate and could damage the impeller.

Leaving the inlet valve open, I now open the third valve, making sure it discharges into a suitable container, ie a bucket. Giving the filter a gentle shake seems to help dislodging any debris. Just make sure that the water level in the tank does not drop below the filter&#39;s nornal discharge line, as you would be sucking air into the filter, which can be a pain to remove with some filters (including the fluval&#33;)

I do this about every second water top up, or roughly about monthly. This way the filter is unlikely ever to block up and there is no way the friendly bacteria can be hurt as tank water at the right temperature is used to do the cleaning.

When finished, reverse the above steps, ie close valve at filter inlet and close the valve at the tee-pice. To avoid a lot of dust (dislodged inside the cannister fom back-flushing) being blown into the tank, I do an additional flush, but this time in the normal flow direction. To do this, I close the valve at the filter inlet and disconnect the discharge line at the pump side of the outlet valve. By by opening the filter inlet valve, I let gravity do its work and discharge a few liters from the outlet of the filter into the same bucket mentioned above. Once completed, reconnect all lines, open up the filter outlet valve, switch the filter back on and you&#39;re in busness again.

I hope the above makes some sense to someone, but as it works for me, I&#39;d be happy to expand if needed.

Happy flushing.

Cheers

Peter

[wombat1100]

Thanks Peter,
sounds like a good idea, what type of media are you using in the filter?
I assume that the backwashing is gravity fed from the outlet pipe? not powered in any way?
Daz

[GoGuppy]

sounds like a good idea, what type of media are you using in the filter?

Daz[/b]

Hi Daz
Good question&#33; I hadn&#39;t cleaned the filter for a long time, so I looked in my Tank Log Book (is it just me, or does every aquarist keep a log of FT events, fish bought, filter cleans, light tube replacements, etc, etc???) for the filter set up and to see when I did the last clean. To my surprise, the last entry of a filter clean in the log was in May 2003, after returning from a 4 week holiday, only to find the tank resembling pea soup :ohmy: &#33;&#33; Apparently, our house sitter emptied half a container of flakes into the tank feeding the fish during this period (needless to say we have managed quite well without a house sitter ever since :biggrin: ).

After experimenting a fair bit with the various types of filter media available over the years, I have settled on the following set up in my old trusty Fluval 203 bought back in &#39;98:

Bottom tray: mechanical filter media, comprising electrical insulation tubes made of white ceramic material of approx 9mm outside diameter (OD) x 4mm inside diameter (ID) x 4mm long which I picked up in a kg batch in a back street &#39;hole in the wall&#39; shop in Hanoi while visiting there for work.

Mid tray: Eheim substrate biological filter medium made of sintered glass of random size, but generally between 3 and 5mm.

Top tray: Fluval Biomax biological filter medium made of 16mm OD x 5mm ID x 20 LG sintered glass tubes.

I have done away with fine filter floss, as it would probably require more frequent filter maintenance (certainly more often than yearly).

I have also used Sera Black Peat to condition the tank water when I had numerous Sth American cichlids and tetras, but I used to put a handful into the foot part of an old nylon
stocking tied in with a knot and placed in a back corner of the tank. This worked well.

To remove medication, algae killer and other chemicals, I have used activated carbon in a small second filter hung off the side of the tank, and have also used this little filter to provide extra cleaning with fine filter floss on the odd occasion. Unfortunately I broke its suction tube recently and need to buy a repacement tube or filter, as it is useful in any case as a back up filter.



I assume that the backwashing is gravity fed from the outlet pipe? not powered in any way?

Daz[/b]


Yep, just good old gravity doing the work of back flushing :rolleyes: .

Cheers

Peter

[joz]

It&#39;s interesting the type of media people use.I&#39;ve always found different grades of sponge best for cannisters.
The little ceramic tubes bock up to fast resulting in greatly reduced biological filt=ering function.
They are best suited for trickle situations where the water is first filtred via a dacron matt.

But these are just my opinions :)

[Sloory]

Thats a good idea ya got there GG.

You should do a bit of an article with some pics and drawings explaining the fuctions and such.
We could do with more instructional articles. :)

[PeteFromTassie]

I clean my canister every month or so, but my tank is quite overstocked and I&#39;m trying to keep nitrates as low as possible... I only rinse out the mechanical media (filter wool) and leave the bio media dirty. I rinse that out maybe 6 monthly.

Cheers,
Pete.

[GoGuppy]

Thats a good idea ya got there GG.

You should do a bit of an article with some pics and drawings explaining the fuctions and such.
We could do with more instructional articles. :)[/b]


I have shown a sketch of the system below, I hope it makes some sense :wacko: .

[attachment=2212:Backflush.doc]


Things to remember are;
-- When backflushing make sure the normal discharge point remains below the water level, otherwise you draw air into the filter which can be a pain to get rid of.
-- When finished backflushing, drain the dislodged dust that hasn&#39;t been revoved by closing valves B and C, then disconnect the hose at the filter side of valve B and open valve A. This will cause the water to flow in the normal direction through the filter and clean the loose particals into the bucket. (Oh yeah, put the bucket under the disconnected hose first, duh...). I normally let the water flow by gravity in this way, but you could switch the filter pump on to provide a stronger flow for a while.
-- Let the water run this way for a short while until the water coming out of the filter looks clean, make sure the filter is switched off and then with a confident, quick motion reconnect the hose to the closed valve to prevent air being trapped. Open valve B and switch the filter back on again.
-- Empty the waste bucket onto the flower beds in the garden, they&#39;ll love you for it.



It&#39;s interesting the type of media people use.I&#39;ve always found different grades of sponge best for cannisters.
The little ceramic tubes bock up to fast resulting in greatly reduced biological filt=ering function.
They are best suited for trickle situations where the water is first filtred via a dacron matt.[/b]

I found that sponges generally block up quicker than the tubes I use and this probably explains why get away with annual cleans, or even less often :biggrin: .

BTW the little tubes I use are of a solid ceramic material and there for mechanical cleaning only, and have no impact on the the biological media tubes higher up in the filter. But in any case, I suggest that a little experimentation may be worth while, as each individual tank set up is different in many ways, ie tank size, fish loading, substrate, water conditions, filter flow rate, types of fish kept, etc to name but a few.

Cheers

Peter

[wombat1100]

Well done Peter, thanks heaps .
@Marc, maybe this shoud be a sticky?
dazz

[Marc]

Yeah I think it might be time to add a DIY section to the site, and this a great writeup to kick it off :)

[vrssbt1]

i clean my native&#39;s filter once a month and the tropicals (guppies,mollies as feeders) every week as there is always babys in the filter

[joz]

Yeah I think it might be time to add a DIY section to the site, and this a great writeup to kick it off :)[/b]

Sounds like a plan Marc.
Many DIY projects around for this hobby :)