Second filter?

[fat_leroy]

I have a 70 litre tank with 8 black phantom tetras and 4 dwarf gouramis in it. I was told that the maximum amount of fish that can be kept in a tank depends on the filtration capabilities. I currently have an interpet PF2 internal filter that is suitable for 45-90 litre tanks. If my tank is currently fully stocked, would adding a second filter, perhaps one which hangs on the back, allow me to add a few more fish.

All i wanted to add were some cardinal tetras, but i don't want to add them if it is not fair on the fish, or likely to cause an ammonia crash.

If i am being stupid here please tell me. Thanks.


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[BBradbury]

More Tank Filtration

Hello leroy...

You don't need another mechanical filter. Just change a little more tank water and do it a little more often. Many tank keepers believe if they have a lot of filters in the tank, the water is clean enough for the fish. I can tell you it really isn't. Filters simply take in dirty tank water and return the same water that may be slightly cleaner. The large, regular water change is what keeps the tank water safe for the fish and plants.

Just remove and replace half the tank water every week and replace it with pure, treated tap water and you'll have no tank problems.

B

 

[gilpi]

Another filter wouldn't hurt and might keep your water cleaner but as BBradbury says...
You can't substitute water changes no matter what or how many filters you have. Fresh clean water is the best thing you can do for your fish.
I have actually kept fish in tanks without filters just doing daily or every other day big water changes and the fish have been healthy and grown at a fast rate.

 

[dalto]

You need both proper filtration and appropriate water changes. Neither is a substitute for the other in most circumstances.

Your filter does a few things for you:

• It provides water flow/current
• It removes particulate matter
• It has material to support the growth of beneficial bacteria for the nitrogen cycle.
• It can help keep the water oxygenated

Water changes on the other hand remove the nitrates and dissolved solids that are present in the water.

 

[fat_leroy]

Thanks for the advice guys, i wasn't implying that i would stop doing water changes, i was just wondering if adding a second filter would increase the number of fish i could house in the tank.


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[BBradbury]

Water Changes as Filtration

You need both proper filtration and appropriate water changes. Neither is a substitute for the other in most circumstances.

Your filter does a few things for you:

• It provides water flow/current
• It removes particulate matter
• It has material to support the growth of beneficial bacteria for the nitrogen cycle.
• It can help keep the water oxygenated

Water changes on the other hand remove the nitrates and dissolved solids that are present in the water.

Hello dalt...

The large, frequent water change does all the things you've listed, without the need for much mechanical filtration. By changing a lot of tank water and doing it often enough, you mix oxygen into the water (aerate) as the tank fills, you remove all dissolved toxins from dissolved plant and fish material more efficiently than beneficial bacteria. The difference is, you're replacing the old, used water with pure water. Not just running old water through a filter over and over again.

Tank water that's continually filtered through media loses its mineral content. Minerals that are important to everything that lives in the tank. By constantly flushing pure water through the tank you're always replacing the minerals.

I'd go as far as to say if one would be willing to change half the tank water daily, there would be no reason to keep mechanical filtration. But, only 1 in 100,000 tank keepers would be willing to do this, so there's a need for filters in most tanks.

B

 

[Mama Karoti]

You need both proper filtration and appropriate water changes. Neither is a substitute for the other in most circumstances.

Your filter does a few things for you:

• It provides water flow/current
• It removes particulate matter
• It has material to support the growth of beneficial bacteria for the nitrogen cycle.
• It can help keep the water oxygenated

Water changes on the other hand remove the nitrates and dissolved solids that are present in the water.

This. Good explanation of the importance of the two.



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[dalto]

The large, frequent water change does all the things you've listed, without the need for much mechanical filtration. By changing a lot of tank water and doing it often enough, you mix oxygen into the water (aerate) as the tank fills

This is one-time aeration as opposed to ongoing. Unless you have a light bio-load your fish could easily be oxygen deprived in less than a day.

, you remove all dissolved toxins from dissolved plant and fish material more efficiently than beneficial bacteria.

But once again, only at the time of the water change. Without the presence of bacteria for the nitrogen cycle the ammonia will build between water changes. With the presence of the bacteria the ammonia is constantly being removed.

I'd go as far as to say if one would be willing to change half the tank water daily, there would be no reason to keep mechanical filtration.

For the reasons stated above this would only work with the appropriate low bio-load. Even with daily 50% changes your fish would run out of oxygen or become ammonia poisoned in between changes.

Please keep in mind, I am huge proponent of large water changes. I used to do 80% weekly changes in all my tanks. I just wouldn't advocate doing larger water changes instead of proper filtration.

 

[gilpi]

Adding another filter as I said before will help if you want to increase the bio load, you now have two filters doing the job of one but as it was also mentioned, you're still using the same water, meaning nitrates will still build up. The advantage is that it will keep the more harmful ammonia and nitrite levels down.
As far as water changes, the more the better.
After raising discus and hanging around discus breeders is when one realizes the importance of water changes to the point that filtration is almost meaningless, yes it is a big commitment to change 80% water on a daily basis but when you see the fish practically grow and healthy right in front of you, there's very little to argue.

 

[fat_leroy]

I understand the biological side of things, and thank you everyone who replied. I guess my question was, would adding another filter increase the rate at which ammonia is turned to nitrite and so on, allowing me to house more fish. I was aware that water changes would still be necessary however.

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[gilpi]

I understand the biological side of things, and thank you everyone who replied. I guess my question was, would adding another filter increase the rate at which ammonia is turned to nitrite and so on, allowing me to house more fish. I was aware that water changes would still be necessary however. Sent from my GT-I8190N using Aquarium Advice mobile app

I know we are getting a bit off topic but to answer your question.. Yes.

 

[ScaryFatKidGT]

I'd get another filter, wouldn't hurt, and maybe a plant... Java fern or moss?

A filter like a Fluval C or Aquaclear or Marineland penguin with a Bio are would be good.