# What media to use in a external canister filter(planted tank)



## royalbijoy (Jul 4, 2012)

Hello All,

I have an almost heavily planted tank(red lotus, vals, banana plant, ludwigia....) . The tank has two filters. One external 1800L/hr and one internal 1000L/hr filter with sponge medium. The internal filter with sponge medium gets dirty every other day(dark brown stuff comes when rinse). The external canister filter gets rinsed once in a month and its almost always clean when I clean it.
The filter media in external filter is round clay balls and ceramic blocks.

My question: Do I need these biological filter media in my planted tank? I guess all the nitrate gets consumed by the plants itself, with the canister not playing an important role. 

If I toss all the biological medium with sponge , will it create any problem? My cheap internal filter with sponge, does a very good job at filtering the dirt in the tank. But I still have lots of dirt on the plants and so I am looking at improving the mechanical filtration. I have doubts about the efficiency of the external filter which I agree would be good in a gravel based substrate without plants(typical African cliched tank). But mine is heavily planted and I doubt it is doing its job.... Please advise.


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## KlintZquarium (Jul 22, 2012)

What brands of filters are you running?


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## Diana (Jan 14, 2010)

The only sponge you have is getting full too fast, so add more sponges.
I would set up the canister with more sponges and floss, less bio media. 

Planted tanks do need some bio media, but the beneficial bacteria live on the sponges just fine, so stuffing a filter with coarse and medium sponges will provide both mechanical and biological filtration. You might use a thin sheet of finer floss, but it tends to block the flow if there is too much debris to be trapped. 

In doing this switch do not throw away all the bio media. At the current time the tank is dependent on it for some nitrogen removal. Put about a third of the bio media into several mesh bags and hang them inside the tank where there is good water movement. Put sponges in the filter where you have removed the bio media. Remove the bags about one a week. This will provide a gradual shift away from the bio media and allowing the bacteria to grow on the sponges. A month later you can remove more of the bio media in the same way. 
At that point your external filter will have about 1/3 coarse sponges, 1/3 finer media (medium sponges and a bit of floss) and 1/3 bio media. 
You will have spent about 2 months gradually encouraging the bacteria to move over, and you will have had a chance to see how good a mechanical filter you have. 

You might find that you have to move the intake around in the tank to pick up the maximum debris, or you might want to move the internal filter to make a better current in the water, to carry more debris toward the intake of the external filter. 

I would run just a very coarse sponge in the internal filter and see how that does. It may still trap quite a lot of debris, but not plug up so fast.


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## royalbijoy (Jul 4, 2012)

Now that's some intelligent answer. I guess I will try that and see if the canister can act as a mechanical filter too. By the way, my external is branded 'aquazonic'(I guess it is a Chinese brand since it didn't have much specs on it). Not a very popular one but the LFS guy had a couple of them in his own tanks and said they did the job. The internal filter I have is also a Chinese brand but has been successfully running for around 2 years now. If I knew the external canister was this bad at filtering, I wouldn't have brought it. The internal filter just costed me 1/10th of the canister..... 

Just got worried reading some forums that biological filtration was the main filtration needed and canisters were best for that. I feel the plants are doing the biological filtration and so I did not really have to go for bio media in the canister.
Regarding the efficiency of the filters, it is easy to find that my external has a better flow rate compared to the internal filter, but the efficiency of the internal is much much better than the canister. The only problem with the internal is that it gets clogged very fast and if I do not rinse it every other day, the tank gets messy.


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## Diana (Jan 14, 2010)

Biofiltration is much less important in a planted tank. The plants are doing a lot of the work.


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## Complexity (Jan 30, 2008)

I don't think it's fair to judge the external canister's filtering ability when all you've put in it is biological media. The canister can't possibly filter out debris without the some form of media for that type of filtration. Put some sponges and filter floss in it and then judge it.

I don't know how large your canister is or how many baskets you have (if any), but here's an idea of how I pack my canisters. Maybe it'll give you some ideas of what you can try for your canister.

I have 4 baskets. The first basket is filled with ceramic rings. This is used to capture large debris, such as plant leaves. I do this to prevent the canister from getting clogged too quickly.

The second basket holds 4 sponges, each about 1" thick. The first two sponges are more course, followed by two more sponges which are finer. This is used as mechanical filtration to remove smaller particles from the water.

The third basket contains biomedia.

The forth basket is split in half. The first half contains more biomedia. After that, I have a layer of filter floss which is then followed by a layer of polishing floss. The filter floss removes very tiny particles while the polishing floss removes the tiniest of particles. At this point, the water should be sparkling clean.

I run two canisters on every tank and alternate regular maintenance and full maintenance on opposite canisters to ensure the biomedia remains stable for the tank.

I perform regular maintenance every 1-3 months, which includes cleaning or replacing the filter floss and polishing floss, cleaning the impeller, and lubricating the o-rings.

I perform full maintenance every 3-6 months which includes the same as above, plus I clean the ceramic rings, sponges, and lightly dip the biomedia in tank water.

There are lots of other ways to do it so take this as just one example. Hopefully, this will give you some ideas that you can use for your own canister.


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## royalbijoy (Jul 4, 2012)

Thanks for the replies. I got a few questions before I deal with the filter.

1. Should the filter outflow be directed towards the plants(plants moving gently all the time) or should it be directed towards the top surface using a spraybar? I feel the water is not clear if I don't clean the internal sponge at least once in 3 days. I heard people clean them once in a month which in my case will leave a muddy tank. Should I get a powerhead just to blow water onto the plants?

2. I currently have a pressurized CO2 which goes to a diffuser and then those micro bubbles get into the input of my canister filter. Is this a good enough method of distributing Co2 in the tank? In my LFS, I saw all those tanks where they just let the diffuser bubble into the water column. Not sure which is best. I dont see any bbubbles coming from the outflow of my canister(hope it is getting dissolved).

3. I just saw one of the PAR glaphs in this forum where they compared the PAR of different lights. I have PL lights(2) and 2 LED floodlights but the tank is not evenly lit. There is a bright focus just below the PL and the the LED's are not that bright at the substrate. They are cheap chinese ones though. SHould I migrate to a T5Ho? If so, how many would be required for a 2 ft high, 4 feet long and 1.5ft deep tank?


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## Complexity (Jan 30, 2008)

royalbijoy said:


> 1. Should the filter outflow be directed towards the plants(plants moving gently all the time) or should it be directed towards the top surface using a spraybar? I feel the water is not clear if I don't clean the internal sponge at least once in 3 days. I heard people clean them once in a month which in my case will leave a muddy tank. Should I get a powerhead just to blow water onto the plants?


There is no "should" in this case. Everyone is different in how they prefer to setup their outflow. As long as you filter the water, you're good.

Regarding cleaning your internal sponge so often, that's once again because you have insufficient filtration overall. As has already been discussed, once you pack your canister with proper filtration media, it can begin filtering the water. That will decrease the work the sponge filter will have to do, lengthening the time before it clogs, which will in turn lengthen the time before you have to clean it. People who clean their sponge filters once a month have good filtration on their tanks so no single filter is overworked.

You cannot make any decision on this until you fix your canister and see how well it is able to filter the water.



> 2. I currently have a pressurized CO2 which goes to a diffuser and then those micro bubbles get into the input of my canister filter. Is this a good enough method of distributing Co2 in the tank? In my LFS, I saw all those tanks where they just let the diffuser bubble into the water column. Not sure which is best. I dont see any bbubbles coming from the outflow of my canister(hope it is getting dissolved).


It is generally not recommended to feed the CO2 into the canister. It can cause the canister to become air locked which can damage it.

You should either put the diffuser in your tank as it was designed to go or, if you do not like having CO2 bubbles in the tank, then switch from a diffuser to a reactor. A reactor mixes the CO2 with the water before it enters the tank so there are no bubbles to be seen.



> 3. I just saw one of the PAR glaphs in this forum where they compared the PAR of different lights. I have PL lights(2) and 2 LED floodlights but the tank is not evenly lit. There is a bright focus just below the PL and the the LED's are not that bright at the substrate. They are cheap chinese ones though. SHould I migrate to a T5Ho? If so, how many would be required for a 2 ft high, 4 feet long and 1.5ft deep tank?


Should you? You don't have to, but you may be happier if you did. I think you'd be better off asking a separate question on lighting in the lighting forum. I'm not the best when it comes to lighting. However, my general recommendation for T5HO would be to get either a 2 bulb fixture or a 4 bulb fixture that lets you turn 2 of the bulbs off. Some people are getting 3 bulb fixtures now which may be an option you'd like to explore. I would definitely get a fixture the spans the full width of your tank so if your tank is 48" wide, then I'd get a 48" fixture.


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## Diana (Jan 14, 2010)

Put the diffuser for the CO2 right under the power head.
Direct the flow from the canister across the top of the tank so the water at the surface shows some pretty good ripples, but no splashing. This will maximize oxygen and minimize surface film. 
Direct the flow from the power head into areas with the lowest flow from the canister, or aim it so the CO2 is best distributed fairly low in the tank. 
Do not aim the power head to counteract the flow from the canister. Make it enhance that flow, improve on it. Better circulation, not turbulence. 

Once you have tried these ideas you can sure move things around to suit your set up.


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