External canister with siphon break valve

[Mark Hewitt]

I'm considering getting a large tank for while I'll use an external canister filter (probably a Tetratec).

However the safety of such an arrangement concerns me. As for best results the intake for the dirty water will be towards the bottom of the tank.

Should one of the seals break on the filter or there would be any sort of leak, almost the entire 35 gallons would drain out and onto the living room carpet! While this is unlikely to happen I need to make sure that it's either impossible or can be contained as the consequences are very serious! - I'd certainly be banned from keeping fish forever!

I did consider putting the filter into a smaller cheap aquarium under the main aquarium big enough to handle draining about half the tank should a problem occur.

But I realise that there is a potentially easier solution, in that I could have a small hole in the intake pipe, just below the normal water level, so if the filter starts draining the most water that can leak out of the tank is about an inch or so before air gets into the pipe and stops the siphon.

However, I don't want to have to switch the filter off and resiphon everytime I do a water change, so is there an easy solution where I could fit some sort of valve / cover so that I can cover it up and thus leave the filter running during water changes then when the water level is back up, open it up again?

Alternatively I could switch my filter off and let the siphon break in every water change, and then re-prime, but would that harm the filter over the longer term?

 

[mfdrookie516]

I dont know how I feel about doing the hole thing. I know people do this with sumps, but I've never seen it done on a canister.

I can tell you that if it is a good idea (somebody else will have to help you with that), you wont need a valve or anything. Your canister will need to be cleaned at least every other week, but cleaning it every week is a very good idea. You're going to have to re-prime it when you clean it, so no problem there.

 

[Mark Hewitt]

I understand, so perhaps just putting the hole in and re-priming after every water change is going to be the best plan.

I might sound paranoid but I do have to assume that the seals on the filter *will* fail and mitigate against it before it happens.

 

[Mark Hewitt]

The alternative is that I just have the filter intake close to the surface of the water. Would this cause significant problems with waste removal if the main intake isn't down low?

 

[Vircomore]

Putting your canister intake up higher wouldn't directly be an issue - but you have to consider this: The main reason a lot of filter intakes are positioned near the bottom of the tank is to draw potentially stagnant water from the bottom. If your canister output is also close to the surface - and you move your intake closer to the surface - you'll need a secondary method for providing increased circulation and exchange of that deeper water so it can reach your intake.

From the things I've heard (a canister owner myself) - canister filters rarely have "catastrophic failures". What are far more common are slow leaks that develop either due to wear and tear on the hose connectors - or an incomplete seal at the O-ring that seals the canister lid to the body. What I've seen a lot of people do, is they set their canister inside a 5-gallon bucket and then install it, so even if a slow leak happens it wont cause much damage because it'll be noticeable that you're missing water before it gets out of the bucket.

You could also buy a "moisture alarm" to put in the bucket (they sell them to put near your washing machine in case of a catastrophic washload failure) and put that in with your canister, so if it starts to leak and someone's home - they'll hear it.

 

[Fishguy2727]

You can turn the filter off without having to prime it again when you turn it back on. Just unplug it and and leave it alone during the water change and you shouldn't have any issues.

I have never had or seen a major leak with any canister. I have seen a couple very slow leaks right after cleaning them, usually because of a rubber seal not sitting correctly. A small pan under the canister and you checking it after a cleaning should be all the prevention you need.

The issue I have seen multiple times is the input disconnecting from the tank and spraying the room with water. This is one reason why I prefer Fluvals. The 05 line has the best tank rim adaptor I have ever seen. I have NEVER had or heard of an 05 Fluval hose coming loose fromt he tank and causing problems.

 

[Mark Hewitt]

You can turn the filter off without having to prime it again when you turn it back on. Just unplug it and and leave it alone during the water change and you shouldn't have any issues.
.

Assuming the water level doesn't go below the syphon intake, otherwise the syphon will be broken?

The reason I was thinking a small hole would work is that it wouldn't be big enough to stop water extraction from still happening at the bottom of the aquarium. But large enough to let air in and break the syphon should water start draining out.

 

[Fishguy2727]

If the water level drops below the intake you will only lose the water in the intake tube fron the intake up to the top of the tank, you won't siphon all the water from the canister up into the tank.

An air hole may simply let air in along with water. Depending on how much air it lets in it may never break the siphon or take a long time, defeating the function you are aiming for.

 

[cabezon]

I have 4 fluval canisters, and I have never had one go catastrophic on me. I have had my sump dump more than 35 gallons of water. the seal is pressed in by the lid. I just bought a 405 the other day used, the seal was ripped, and there still was only a small trickle. the other thing about fluvals is that there is a ball valve built into the hoses, so you could just close it during water changes.

I did have a problem with one canister that had it's output draining into the HOB fuge. the fuge output lost siphon and overflowed and the fluval pumped and pumped. now my intake sits in the skimmer box for the overflow for the unused sump. it will suck air if the level goes down even a half inch in the DT.

 

[Mark Hewitt]

Well I've had my TetraTec EX700 set up and running for a little while now. No problems, but I've got it in a large plastic storage box, which I estimate holds about 15 gallons or so.

It won't contain the entire aquarium water should the filter fail completely, but at least it will contain a leak.

 

[glassbird]

I would like to add a vote for the moisture alarm. I have an eheim 2028 under my 75 gallon tank. It sits in a Rubbermaid tub. I measured the space I had available, and found the largest and deepest tub I could find that would fit. I laid an old towel in the bottom, and use the space not occupied by the filter to house drippy things like nets and my python. At the side closest to the filter cannister, I have the activator for the moisture alarm. The type I have comes with the activator being removable from the siren part, so the activator is on the bottom of the tub and the siren is level with the tank and facing into the room. That sucker is loud...I just hope someone is home when/if it goes off for real! (It cost less than 10 bucks...not bad for a little peace of mind and advance warning.)

 

[ezy33]

A+ on the 5 gallon bucket and alarm. I have 2 Fluval 403 canister filters i ran for 20 years. The only minor leaks came from the operator error and worn connectors. I still use them once in a while now that I went to SW.

 

[iceywater101]

Mark don't worry about it. I have been using Fluval's for years they are made by Hagen so they are the best.

This is just a risk you have to take. What if your stand collapsed one day, do you have a plan to catch all that water.

These are just some of the many risks we take when bringing the wild into our homes for our enjoyment. I know for myself the risks are well worth it.

Good luck and don't let this stop you from getting a larger tank.

 

[Mark Hewitt]

Mark don't worry about it. I have been using Fluval's for years they are made by Hagen so they are the best.

This is just a risk you have to take. What if your stand collapsed one day, do you have a plan to catch all that water.

These are just some of the many risks we take when bringing the wild into our homes for our enjoyment. I know for myself the risks are well worth it.

Good luck and don't let this stop you from getting a larger tank.

Thanks. The bigger tank is in place now, with a plastic box to catch any filter leaks, so I'm happy! (Well I would be if the filter had turned out to be any good, but that's another story!)