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Im seeing more and more posts lately about people not using filtration or water flow, can someone who has been doing this explain your methods of care? Also how do you get away with no water changes? Id be afraid not to do either!
 

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Im seeing more and more posts lately about people not using filtration or water flow, can someone who has been doing this explain your methods of care? Also how do you get away with no water changes? Id be afraid not to do either!
I can't speak for anyone else but I do use filtration on my tanks. Just no man made mechanical filters or water flow on my FW. The filtration is the live plants (and on marine systems the macro algaes). By starting the tank full of fast growing plants and slower growing plants, the tank is filtered, balanced, and stabilized by the plants. The plants consume the fish wastes (ammonia/nitrates, phosphates, carbon dioxide) and convert them into fish food (the plants) and oxygen. By adjusting added food and light the tank stays clear and algae free. For years.

Because the plants are maintaining the tank, ammonia, nitrates, phosphates are consumed so are at 0 regardless of whatever water changes are being done. Carbon dioxide is also maintained low so ph remains high. So that in a 24 hour period the tank becomes a net consumer of carbon dioxide and producer of oxygen. Regardless of what else is going on.

Finally, water changes will never prevent parameter changes just limit the amount of change. The build up between changes must be removed by the water change when a stable system is realized. In order for that to happen, the parameter must build up to:

(the change between water changes)/(fraction of water change).

So say that 10ppm of something increases between 10% water changes, the final value just before the water change is 100ppm. (that is 10PPM/(1/10)=100. It then drops down to 90 then back up to 100 between changes.
If you did a 20% change the value would be 10ppm /(1/5)=50ppm. Down to 40ppm and back up to 50ppm next water change.

So what I do is just let the tank be balanced out with plant life. That works fine for Fw and marine fish tanks. I do have to dose calcium/alk/magnesium with corals in the marine tanks.

my .02
 
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Discussion Starter #3
Thanks very much, very well explained. I appreciate the answer
 

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WoW!! now that's a good explanation lol
 

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more math fun and a web page on non filtered operation

Thanks.

I hope everyone can understand the math.

FWIW if you "tie" the size of the water change to the frequency the number can become interesting. (At least to me anyway)

So consider this math problem:

Given:

1) You are conducting water changes as some multiple of the days between changes. Like 10% every 10 days, 20% every 20 days, etc.

2) Something is increasing at a constant daily rate.

3) The system has been running long enough that the concentration of that "something" is measured as the same just before any water change.

Question to solve for:

What will be that concentration in terms of the daily increase just before any of the water changes? for instance 10 times the daily increase, 20 times or whatever. (it is not 10 or 20 times.)



If you can figure that out I'll award you a genuine beaslbob phantom water change expert gold star. :)


Also here is an interesting page showing the eco jar. Which is an extreme case of this operation:

Self-contained Microcosm

Be sure to click on the picture to expand it.

and notice the very light feeding with a tooth pick.


my .02
 

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Mechanical filtration may not be as imporatant in a planted tank since your gravel contains most of the bacteria, and plants can break down waste to nutrients, however weekly maintanence and vaccuuming is still important. Mulm build up can result in death of plant roots, and benificial bacteria which will throw off the balance.

In most planted tanks water flow is very important. This constant movement helps nutrients, CO2, and even heat spread out evenly throughout your tank. Areas that don't get much flow tend to build up debris and are usually areas that you see algae growth popping up. At night plants use oxygen and give off CO2, so water flow and aeration is important.

Beaslbob's explaination is good but does not quite work as you think with some chemicals. Suppose the ppm is constantly going up faster than you can remove it. Lets start with that 100ppm scenario and lets say that by the end of each week it goes up 20ppm. If you do a 10% water change each week here is what you get:

Week 1: 90ppm
Week 2: 90+ 20= 110ppm (10%) = 99ppm
Week 3: 99+20= 119ppm (10%) = 107.1ppm

As you can see week after week the ppm amount can go up, or if you remove more than 20% a week has the potential of going down. Chemicals in your tank can still go up or down due to the balance of fish to plants. The nutrients for plants can become limiting as they all grow, however if you have fast growing fish and slow growing plants, you may see nitrate and other chemical going up faster than the plants can use them.

Sometimes the water change itself is adding the substance. As water evaporates from the tank you top it off, adding more substance that doesn't get evaporated (often hardness). A lot of high tech planted tanks have to add various nutrients to the tank in order to keep the plants healthy. They add nitrate, potassium, phosphate, iron,...etc because the plants are using this stuff up faster than a normal water change can add it back in. However, when using the "lazy" method they reset these ppm each week by doing a very large 50% or more water change.

Long story short, it can be done but you have to keep in mind that unless it is a completely closed off system like an eco jar, you should still test the water paramaters at least every few weeks or months and adjust your normal water change as needed. Watch to see how your plants and fish are doing, and know some of what is in the new water you are adding. Fine tune your lighting, hours on, etc.

One of the better self-sustaining setups uses "mineralized" soil as a substrate. This means you should not have to feed your plants for years, but you still have to do normal water changes and test your water from time to time.
 

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....

Beaslbob's explaination is good but does not quite work as you think with some chemicals. Suppose the ppm is constantly going up faster than you can remove it. Lets start with that 100ppm scenario and lets say that by the end of each week it goes up 20ppm. If you do a 10% water change each week here is what you get:

Week 1: 90ppm
Week 2: 90+ 20= 110ppm (10%) = 99ppm
Week 3: 99+20= 119ppm (10%) = 107.1ppm

...
FWIW the analysis I presented represents what the tank will be at once the value before each water change is the same.

In your example you are changing out 10% of the water each week with a 20ppm increase between water changes. Assuming 0 in replacement water and applying the above equation:


(build up)/(fraction change)=(20ppm)(10/100)=200ppm

Reagardless of what the initial values was (90, 50, 10, 500 300, 200ppm) the tank winds up at 200ppm which is why at 90 it is still increasing each week. the tank winds up at 200 then down to 180 after the water change and back up to 200 then next water change.

One my tanks setup with sand in 2002 I do have a build up of both kH an dgh to very high levels. On my 2 year old tank with peat moss kh has been 4-5 degrees an dgh 9-10 degrees for th eentire 2 years including initial setup. So the peat seems to be helping keep those constant and neon tetras seem to need that.

my .02
 

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The analysis I presented was correct but I did leave out the amount in the replacement water. basically the final value is increased by whatever is in the replacement water.

final value before water change=(change between water chang)/(fraction of water change)+amount in replacement water

This is a "fun" exercise but what it is really supposed to "spark" are some questions.

1) can water changes at "normal" (whatever that is) really maintain an aquarium.

2) Or is the real problem to solve to get the buildup down to 0.

To me it is the later. But perhaps you-all can chime in. (I am in the south. :) )
 

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Oh, I was agreeing with your math beaslbob. :) My point was how high can your fish/plants/algae tolerate of substance X. For some things it is definately not 200ppm. On top of natural filtration, water changes are still necessary and the amount depends on a number of factors I was listing above as well as others I can't predict. The flip-side is how low can a specific ppm go if you change out too much water and are not replenishing with enough of substance X that a plant needs.

Dirtydutch sounds like he is asking about a set up and forget tank, and although you can get away with filtration, I think routine water changes, the ocassional water testin, and good circulation is still important, unless you are talking about a completely closed micro ecosytem.
 

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Discussion Starter #10
I like the idea of both setups actually, I think I may just give it a shot both ways and see what happens. what are some of the best possible plants for this? thanks you guys are filled with info*pc
 

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I'm wondering about people who dont use any type of filtration & dont have live plants. I have a one and a half gallon with filtration & no live plants. It just has one female betta & an aquatic snail. Just curious is it safe for the fish to live no filtration or live plants? Does it shorten their life span.
 

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I'm wondering about people who dont use any type of filtration & dont have live plants. I have a one and a half gallon with filtration & no live plants. It just has one female betta & an aquatic snail. Just curious is it safe for the fish to live no filtration or live plants? Does it shorten their life span.
Bettas can do fine in that sort of set up (since they can breath air) and the snail, if it's not particularly large, wouldn't have a temendous impact on things so long as water changes are done . For other types of set ups , I'd think there would need to be a constant waterchange system in place to remove pollutants otherwise the water would foul quickly. Many Asian breeders use a constant change system which eleminates the need for filtration since all of the water is changed over the course of the day.

It should be noted that the concept of no waterchanges works well with tanks that are heavily planted and very lightly stocked, but they begin to lose their filtration abilities as stock levels increase. At some point disolved organics reach a point where they can begin to cause problems, particularly as stock levels increase. Cichlid tanks simply need waterchanges. They are far too messy and produce way too much waste for a planted tank (provided the cichlids didn't destroy the plants) to absorb . I have never been able to successfully keep cichlids and plants in the same tank, so waterchanges have been a way of life. Typicly I perform 80% weekly . While this isn't for everyone , this level of waterchange (along with my habit of light stocking) keeps pollutants from acumulating to significant levels. I've been doing this for quite a while and it works very well , though it is a bit of a chore when your tanks are over a hundred gallons but healthy fish are worth it IMO.
 

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This was a very educational thread, cuz i wish to put plants in my tank, now i have just that much more information. Very well done to all of the above!!!
 

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Oh, I was agreeing with your math beaslbob. :) My point was how high can your fish/plants/algae tolerate of substance X. For some things it is definately not 200ppm. On top of natural filtration, water changes are still necessary and the amount depends on a number of factors I was listing above as well as others I can't predict. The flip-side is how low can a specific ppm go if you change out too much water and are not replenishing with enough of substance X that a plant needs.

...
The key is to consume wastes being created like nitrates and phosphates so that they are 0 regardless of the water changes. Even if the replacement water has nitrates in it.

And to buffer to prevent builds up like hardness. (peat moss) or losses like calcium/magnesium/iron

But I do agree a more common problem especially for saltwater reef tank is the plant life may actually reduce things too much through filtering as well as consumption (halimeda for calcium carbonate). Which is also complicated by the fact that many things like potassium to not have accurate test kits available for the home hobbiests.


FWIW I just had to replace a leaking 20g l. Seems after 25year it developed a leak.


photo immediately after setup of new tank




12 hours later:




24 hours later



48 hours later:






I find that amazing even after witnessing it many many times over the last 30 years. I do now use a different method to prevent the cloudiness in new tank, but could not avoid it in this case.


my .02
 
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