# Canister filter o ring



## kenshinH (Jun 1, 2013)

How often do you replace a canister filter o ring ? Only When it's leaking ? Or every time you clean it? A friend mine told me that every time a canister gets open the o ring gets weaker is that true? He doesn't have an aquarium but a swimingpool. 

I found the right size o ring for the sunsun 302 at Leslie's pool supply but the cost is half of the filter($25) so if I clean my sunsun twice a year it will cost me $50 if I replace the o ring every time I will open it so I go back to my question is it necessary to replace o ring every time you open a canister filter ? Or just replace it when it leaks?


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## Icegoalie32 (May 8, 2012)

Once a year for me. Peace of mind. I have 5 Fluvals. I replace one every other month on a regular rotation.


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## photoman (Mar 28, 2010)

I've got an Eheim 2215 and a 2217 running on a 75 gal. Both filters have been in service for several years. Same O rings with no need to replace. It's not like they're under high heat, pressure or stressful situations. I think replacing these for no reason is tossing money away.


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## rrogan (Nov 5, 2007)

I have an Eheim 2217 that I bought maybe in 2008. I used it for 2 years or so and then it got put in storage until just a few months ago. I inspected the o-ring, and it was perfectly fine and it's running now with no leaks. It's been disassembled countless times as well. You should be able to tell when it needs replacement by just inspecting it whenever you take the filter apart. Look for any sort of blemishes on it that could potentially cause leakage.


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## kenshinH (Jun 1, 2013)

i bought my 302 sunsun last year June 2014 it took two cleanings to make it leak 😄 I went to Leslie's pool supply and got an o ring for it for $25, comparing the one that came from the sunsun to the leslie brand it's night and day difference, the ones from Leslie's and a bit thicker and when you drop the canister head from the body you can feel the air tight seal, it's pricey but you have a piece of mind


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## DayOlder (Jul 12, 2014)

302 O-rings $4 at http://www.americanaquariumproducts.com/ViaAqua750CanisterFilter.html#O_ring They also carry impellers for most sunsuns.


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## kenshinH (Jun 1, 2013)

DayOlder said:


> 302 O-rings $4 at http://www.americanaquariumproducts.com/ViaAqua750CanisterFilter.html#O_ring They also carry impellers for most sunsuns.


I'll save that link and order from them next time, do you think it's the same quality as the Leslie's o rings?


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## DayOlder (Jul 12, 2014)

kenshinH said:


> I'll save that link and order from them next time, do you think it's the same quality as the Leslie's o rings?


While I have ordered then and have them I have yet to use them. I always keep spare everything. My Sunsun is only four months old so I have not changed out anything yet. The O-rings seen the same as the one that came with the canister.


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## kenshinH (Jun 1, 2013)

DayOlder said:


> While I have ordered then and have them I have yet to use them. I always keep spare everything. My Sunsun is only four months old so I have not changed out anything yet. The O-rings seen the same as the one that came with the canister.


In comparison the o-ring from leslies and from the sun sun is different, leslies o-ring is firm and thicker, the sunsun is flimsy and smaller.


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## roadmaster (Nov 5, 2009)

I clean the filters each month and lube the O ring's with vegetable oil or Vaseline to help keep them from drying out over time and or cracking.
Been using the same O ring's on my eheim's for about three year's now.


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## Clear Water (Sep 20, 2014)

I keep spare o rings and only replace as needed. I had one leak the other night and took the filter apart and cleaned the o ring and it was good to go again. I have never seen one wear out and break when the filter is up and running but more when the filter is down to clean.


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## THE V (Nov 17, 2011)

After some time the rubber becomes more stiff and can form flat sides. The first sign of an o-ring issue isn't normally a leak in my experience, the filter starts sucking in small amounts of air. 

I order mine online and thet generally arrive within a week. In the meantime I turn the filter off and give it a good cleaning. Major reason I have two filters on the tank.


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## chad320 (Mar 7, 2010)

I second the Vaseline suggestion. It works great on all sorts of O-rings.


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## klibs (May 1, 2014)

Use silicone grease instead of vaseline to lube up o-rings. This will greatly prolong the life.


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## AndreyT (Apr 28, 2011)

THE V said:


> The first sign of an o-ring issue isn't normally a leak in my experience, the filter starts sucking in small amounts of air.


Canister filter installed _under the tank_ works under a fairly significant amount of positive water pressure inside. How can it possibly suck in air? Through the intake tube - maybe, but throuh the O-ring on the canister itself... how?


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## THE V (Nov 17, 2011)

The pump on most canister filters is right before the outlet line into the tank (Magnum 350's are reversed). This means that the pump is pulling water through the media and there is a negative pressure inside of the canister. Only if the o-ring on the return is fails will you get a leak.

When the magnum 350 main o-ring cracks you get a flood (why it is gathering dust in the garage).


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## Kibblemania1414 (Feb 1, 2011)

I would replace them once a year max... didn't learn that till after I had a leak :|


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## AndreyT (Apr 28, 2011)

THE V said:


> The pump on most canister filters is right before the outlet line into the tank (Magnum 350's are reversed). This means that the pump is pulling water through the media and there is a negative pressure inside of the canister.


No, that does not mean that there's "negative" pressure inside the canister. The only thing it means is that the pump _lowers_ the pressure after the media. The pressure after the media is lower than pressure before the media. This difference in pressure is what forces water to flow through the media.

However, at no point the pressure inside the canister becomes "negative", i.e at no point the water pressure inside the canister drops below atmospheric pressure. An impeller pump of such miniature size is absolutely incapable of producing such a massive pressure drop. That's just ridiculous.

In short, the pressure inside the canister varies, but absolutely everywhere that pressure remains _way_ above atmospheric pressure.



THE V said:


> Only if the o-ring on the return is fails will you get a leak.


No. If any o-ring at canister level fails, you will get a leak. Water will leak out of the canister, not air into the canister.


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## PhysicsDude55 (Oct 24, 2011)

Only replaced 1 O-ring on my 3 canister filters that have been running for ~4 years.

I keep an extra one on hand, but only replace it when it leaks.

I have a spare of each major component for all my filters that I bought online pretty inexpensively. No need to replace them unless they fail IMO.


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## Clear Water (Sep 20, 2014)

PhysicsDude55 said:


> Only replaced 1 O-ring on my 3 canister filters that have been running for ~4 years.
> 
> I keep an extra one on hand, but only replace it when it leaks.
> 
> I have a spare of each major component for all my filters that I bought online pretty inexpensively. No need to replace them unless they fail IMO.


This is good advise. Having spare parts on hand will keep your filter running and will keep you from running in the panic mode to get parts when it's down.


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## tiggity (Feb 21, 2012)

I apply silicone grease every time I service my canister (3 mo). No issues, canister has been running 2 years with the same O-ring.


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## demonr6 (Mar 14, 2011)

I have an off-brand Sun-Sun knock off I bought on eBay. When something breaks, I will buy a new one. Spending half of what it cost on an o-ring is not going to happen.


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