Anyone do a filterless tank?

rdmpe

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May 4, 2003
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There are some articles around about heavily planted tanks with no filter, just a small powerhead for circulation. Anyone have a healthy tank of this sort?

I plan on reducing the filtration of my 30g planted tank over the next week or so and monitoring the amonia / nitrite levels. I have reduced the stock a lot. I currently have:

2 gourami @ 3" <--- edit - I have two, not three
2 gourami @ 2"
1 weather loach @ 3"
1 SAE @ 3"
1 unknown cat @ 1"
1 oto cat @ 2"
6 oto cat @ 1"

Well, looking at that list, the stocking level is not all that light. However, I'm not sure how much the oto cats count since they are mostly scavenging and eating algea. I think that since it is a well established tank, I will probably be OK.

My primary concerns are monitoring the amonia and nitrite and possible low oxygen levels at night. I think that the gourami will be OK since they are a labyrinth fish, but the loach and cats may suffer if the oxygen gets too low. I add CO2 and it is usually between 15 to 20 ppm.
 
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I haven't done one myself, but I've read a bit on them. Personally, I wouldn't even try it with more than 3 of your Gouramis and maybe 5 or 6 Ottos. I would probably keep your SAE also. When they say to lightly stock a filterless tank.....they mean it. You will have alot of pollution being deposited in a tank that won't be able to grow a decent sized bacterial colony to deal with it.

Our filters are able to house a larger amount of bacteria in a smaller space than is normally able to be done in nature. You really need to look at getting things as close to natural as possible before trying to remove filters. Most people are unwilling to have few enough fish in a tank to use this method. You would have to pretty much split your inhabitants into two or more tanks (of the same size) to be able to do this for any amount of time. I also agree that labyrinth fish are a good choice for a tank of this sort. Your Corys are also capable of gulping air from the surface (they actually require the ability to do this) but are terribly messy for their small size. Catfish of all types seem to be heavy polluters.
 
If you want to get the quiet, peacefull benefits without losing the filter benefits, try using a submersible sponge filter like the Simple 1, 2, 3 or Simple 4 that Hagen makes. I use one on my RFUGF (See enter my tank, below) and it works great.

Chinaboy, if you reduce surface turbulence, you really cut down on CO2/ air exchange at the water surface.
 
hey matak, just want to ask you.
how is your tank doing? the tank im STILL planning for very similiar to yours. 36L x 12W x XX Height.
120 watts of normal fluorescents.

i love amazon swords and tall plants like vals.

are you having any problems with the plants in your tank? thanks
 
filterless

I think I may remove the two small gouramis which I was planning to do anyway. Also I only have 2 gourami @ 3", not 3. That was a typo. Have to keep the SAE and Oto's since I have 4.3 watts/gallon of CF lights and those fish are doing a great job at algea control.

This tank is very heavily planted and also has a large pile of volcanic rock which is very rough and porous. I realize that it isn't the same as a big wad of filter floss, but the tank may have a strong enough bacterial colony to take care of the ammonia compounds that the plants don't use. From what I've read, plants can utilize raw ammonia more easily than nitrite and nitrate, so they should be happy about it too. I may be wrong, but I have to try it myself in order to be convinced ;)

So my plan is to shut the filter down early Saturday and monitor the water every hour for ammonia & nitrite...
 
Once a tank is well established there is plenty of bacteria in the substrate, rocks etc. to be functional.
I remember back in the day, a guy who used to breed fish, who had the most beautiful 50 gal. tank that was completely filter-less.
It was the most beautiful tank I've ever seen in person.
It had just two large Discus in it, and it was loaded with many varieties of Crypts. As I remember it he did very frequent water changes and that was about it. Very little fertilization. Just a good balance.
Len
 
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