Are canister filters bad for Discus?

[tony8028]

After going to some expense to provide what I thought was a good solution for my 60 gallon tank, I now read that canister filters are bad for discus because unless they are cleaned on a weekly basis they trap a certain type of bacteria that causes ammonia spikes of something like that?

The advice of this guy was to only use sponge filters - nice cheap solution, but seems somewhat underpowered.

As for washing the filter media on a weekly basis, this also goes against so many other articles I have read that have to do with not disturbing bacteria too often.

I am currently running an Aquel 500 canister as well as an over flow filter that is built into the tank, along wth one regular sponge filter.

interested in opinions.

[cooper666]

A canister filter should be fine. Just fill it with a quite open pore media, bioballs or similar. Avoid fine things that will trap filth (these are the bits that need weekly cleaning) I ran a canister for years, inside was 100% bioballs. Inside the tank, on the filter inlet, I had a large sponge which use to get changed once per week, the internals of the canister never got serviced and never blocked. That was on a marine - fish only tank.

[tony8028]

I ran a canister for years, inside was 100% bioballs. Inside the tank, on the filter inlet, I had a large sponge which use to get changed once per week, the internals of the canister never got serviced and never blocked.

Thanks - my canisters have a layer of filter wool as well as some course media - so you think piff these in favour of some bio balls?

How can I make changes like this without having an impact on the bio balance of my tank?

I assume this media will be holding some bacteria that will then be replaced my new noodles / bio balls that contain zero bacteria initailly.

[cooper666]

Yes, changing media will upset the balance. Do it slowly, a little at a time. You could also cut down the feeds, exchange more water or both.

It is still very important to have a fine filter somewhere in front of the bio media, It's just easier to service if its not in the canister.

You can leave it as is to but be sure to clean the solids filter bits regularly, if you skip the maintenance that's when problems occur.

[tony8028]

Thank you @cooper666

[Second Hand Pat]

Hi Tony, I think Cooper is referring to a prefilter on the inlet to the canister to catch bits of food and whatnot from entering the filter to keep the canister insides clean. Many here use canisters. One downside to canisters is when the power goes out the inside of the canister goes toxic (bacteria dies due to lack of oxygen in a closed environment). If this gets pumped into the tank once the power returns it can hurt the fish. I have read the die off can happen in as little as two hours.

So if the power goes off best to open up the canister and remove the bio-media and place in an bucket with water and unplug the canister until the power returns. Then place the bio-media back in the canister and plug it back in. Perhaps others can confirm this.

Personally I am not a fan of canisters. I was an early user, priming and running them without leaks around the seals are a PITA. I'm sure today's canisters are better about that.
Pat

[slicksta]

Canisters are not bad, they just require an effective maintenance schedule. I've never heard of the problem of trapping bacteria causing Ammonia spikes. What can happen is if it is not properly maintained and the flow is reduced, people then have the tendency to over clean it, disrupting the bacteria greatly and causing an Ammonia spike. This can happen especially if you do not use tank water to rinse the media or change out too much media at once.

Coop' has has given you some good advice. I've always filled mine with free flowing media such as large cell sponges and small bio_balls. A pre-filter on the intake is Also a good idea.
Never replace media, just rinse it out in tank water. And if you do need to replace a sponges, do 1 and wait a month before replacing any other media.

I don't know how you are using your overflow, but mine is filled with bio_balls and topped with 2 layers of sponge and a disposable piece of floss at the top. This works well for me as a prefilter but there are a few things to be aware of. If the floss clogs you can overflow the tank. So I have a bypass to allow water past the floss if I forget. I also have a high water sensor that'll send me an alarm way before it becomes a problem.

Lastly I'd add, since you have an overflow, consider doing some sort of sump filter in the future... Much easier to maintain than a canister.

[tony8028]

Lastly I'd add, since you have an overflow, consider doing some sort of sump filter in the future... Much easier to maintain than a canister.

I really dont have room for a decent sump......i probably have a space of around 2.5 feet under the tank which is where the canister is.

[Dam777]

Unless you maintain a very strict maintenance schedule they can and will cause you problems. Not just the canister, pre-filters and sponges that need cleaning, its the hoses and all related fittings that are the biggest PITA, and believe me they will get gunked up. Ive tried them all all on my 90 and went with two AC 110's, much easier and do a great job. My new 125 is gonna have a 50 gal sump which I hope makes things even easier. Hope this helps.