# water changes... really? are they necessary? debate



## rnsheehan21 (Mar 6, 2011)

after talking with some of the guys at work i am really beginning to question this idea of water changes being necessary.....that is if you tank is planted........

if you don't have LIVE plants then yes you better change out that water.......but let me reiterate... if your tank is planted i think that water changes are optional.....

why do i say this? because my last tank i had i went 1.5 years with out a water change....my fish, all cichlids, and one chinese algae eater survived ....tank before that, of 3 years of various tetras, same result......these tanks were planted with various swords ......so i just wanted to get some feedback see what others have experienced and to see if others have even tried not doing water changes for awhile......because for some of us who are not as lucky to have neutral soft tap water ....its a pain ...more like a chemistry project then a simple water change....anyway hope this sparks some debate and if you have any questions for me please ask


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## small fry (Oct 14, 2010)

I do believe water changes should be preformed even in a well planted aquarium. I have a heavily planted QT that I change the water twice a month, and the chemistry stays the same and the nitrates never exceed 5ppm, but clean water is important.

First of all, water left in the tank can change chemistry if not changed in awhile. This usually means the water becomes more acidic, but that varies depending on the types of plants and other decor such as driftwood, or chemistry altering rocks. That just maked more problems in the future when you do do a water change, or when you top off the tank. I actually combined my secound point with my first so, um, I don't have much more to say.

I will continue to do water changes in my tank no matter how well the chemistry holds. Fish should have fresh, clean water. I am sure there are other reasons why to change water for a heavily planted tank, but I can't name any right off the tip of my tounge.

_(edit: and why give a fish less attention than they deserve?)_


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## Backer (Sep 18, 2010)

I have heard of tanks that have PERFECT setups, like perfect fish combo and everything and like shrimp and stuff and they completely seal the tank. no 02 or anything. Truly an amazing feat, a little ecosystem in itself, but I have heard of it. I personally kind of enjoy the whole scene of water changes so I don't mind too much.

P.s. my water is hard out of the tap as well. I have just been lucky and haven't had to do anything to it


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## gingerael (Mar 5, 2011)

I have a heavily planted tank that I have not changed the water in for 4 years. I tested the water last week and the levels are all within normal ranges


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## aunt kymmie (Jun 2, 2008)

I'm willing to bet no matter how heavily your tank is planted if you've got a shoal of discus in that tank weekly water changes are mandatory. I'm not willing to find out the answer to that for certain by not doing water changes on my discus tank, heck no. 
That being said, I have a little 6gl very heavily planted shrimp farm that I'm sure would be just fine missing quite a few water changes. I stretch it on this tank, do a water change about three times a month. Would never take a chance like that with my discus.


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## Mikaila31 (Dec 18, 2008)

Ammonia, nitrate, and nitrite are only the basics of water parameters. A tank may stay cycled for years without water changes. However buffering capacity will not be replenished. Since the cycle produces small amounts of acids these do reduce and consume buffering. Along with fish regulatory functions and plant growth. Plants are actually quite good at consuming Ca, Mg, and other minerals out of the water leaving it depleted. This will eventually effect the fish and plants in a chronic manner, it is very hard to undo this kinda damage. Saying fish have been fine for years holds no merit on if the fish are actually fine. Good example of this is I fed my cats Science diet for 13 years, then one ends up with diabetes(13 years old). A lot of research and vet visits later it came down to the fact that years of expensive crappy food eventually catches up with animals. Switched foods(even more expensive now) and kitty instantly went back to non-diabetic. He was on insulin for about a week. Its best for the animal to care for it properly from the beginning. Simply because it seems okay is no reason to assume it is when you are not doing water changes. Failure to provide proper care will eventually catch up and often becomes more work then if you had simply provided proper care from the start.

Even my planted tank that runs like the El Natural method still gets weekly water changes of 30-50%.


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## 1077 (Apr 16, 2008)

rnsheehan21 said:


> after talking with some of the guys at work i am really beginning to question this idea of water changes being necessary.....that is if you tank is planted........
> 
> if you don't have LIVE plants then yes you better change out that water.......but let me reiterate... if your tank is planted i think that water changes are optional.....
> 
> why do i say this? because my last tank i had i went 1.5 years with out a water change....my fish, all cichlids, and one chinese algae eater survived ....tank before that, of 3 years of various tetras, same result......these tanks were planted with various swords ......so i just wanted to get some feedback see what others have experienced and to see if others have even tried not doing water changes for awhile......because for some of us who are not as lucky to have neutral soft tap water ....its a pain ...more like a chemistry project then a simple water change....anyway hope this sparks some debate and if you have any questions for me please ask


 
You would need heavily planted tank (not a few swords), and a balanced fish load that would not produce more organic waste than the plant mass could consume.
Over time,the buffering capacity that water holds would need to be replenished with GH booster (Calcium, magnesium), or plant's would begin to suffer and fish,, depending on species,,would also feel the effects.
Heavily planted aquariums that receive few water changes are possible with afore mentioned balanced fish load in proportion to plant mass.(Is a fine balance)
Heavily planted tank in my view, as well as other's is a tank with no more than fifteen percent of the bottom NOT planted.
Those who run such heavily planted tanks with few water changes, often admit that with increased numbers of fishes,, water changes are needed for fishes health.(too many fishes for plant uptake of organics )
Those who don't admit this.. Are only interested in plant growth near as I could tell,and fishes are almost afterthought, They will tell you that fishes will, as you say.. survive but then goldfish and bettas often survive poor care for some time before dying. What value do you place on fishes?


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## amberjade (May 28, 2010)

I do water changes no matter what - I actually make the fresh water going into my SA tank a tiny bit cooler than the tank, too. My fish all respond really well to it! It's like a refreshing rain. Gets the cichlids into spawning mode, too - not that I see any eggs. My plecs eat them overnight!
_Posted via Mobile Device_


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## rnsheehan21 (Mar 6, 2011)

Backer said:


> I have heard of tanks that have PERFECT setups, like perfect fish combo and everything and like shrimp and stuff and they completely seal the tank. no 02 or anything. Truly an amazing feat, a little ecosystem in itself, but I have heard of it. I personally kind of enjoy the whole scene of water changes so I don't mind too much.
> 
> P.s. my water is hard out of the tap as well. I have just been lucky and haven't had to do anything to it


 
I have seen some of these "perfect" setups...never with fish though but still pretty cool ...glad you mentioned that cause i forgot about those


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## rnsheehan21 (Mar 6, 2011)

gingerael said:


> I have a heavily planted tank that I have not changed the water in for 4 years. I tested the water last week and the levels are all within normal ranges


glad to hear i'm not the only one! thanks for you post


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## rnsheehan21 (Mar 6, 2011)

Mikaila31 said:


> Ammonia, nitrate, and nitrite are only the basics of water parameters. A tank may stay cycled for years without water changes. However buffering capacity will not be replenished. Since the cycle produces small amounts of acids these do reduce and consume buffering. Along with fish regulatory functions and plant growth. Plants are actually quite good at consuming Ca, Mg, and other minerals out of the water leaving it depleted. This will eventually effect the fish and plants in a chronic manner, it is very hard to undo this kinda damage. Saying fish have been fine for years holds no merit on if the fish are actually fine. Good example of this is I fed my cats Science diet for 13 years, then one ends up with diabetes(13 years old). A lot of research and vet visits later it came down to the fact that years of expensive crappy food eventually catches up with animals. Switched foods(even more expensive now) and kitty instantly went back to non-diabetic. He was on insulin for about a week. Its best for the animal to care for it properly from the beginning. Simply because it seems okay is no reason to assume it is when you are not doing water changes. Failure to provide proper care will eventually catch up and often becomes more work then if you had simply provided proper care from the start.
> 
> Even my planted tank that runs like the El Natural method still gets weekly water changes of 30-50%.


you make a great point but i would say the water you use in water changes has an negative impact too....like mine....its really hard, loaded with calcium, and ph is about 8.4 so its pretty hard to do water changes for me....i'v never had problems with fish health. Usually mineral deficiency results in discolored scales, poor fin structure ect. none of which have ever occurred recently in any of my setups


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## SGDude (Feb 12, 2011)

I had a cichlid tank with a UGF and a HOB filter that went for 3 years without a water change. 

Now I have no UGF filters and I can't go for two weeks without a water change.


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## rnsheehan21 (Mar 6, 2011)

1077 said:


> You would need heavily planted tank (not a few swords), and a balanced fish load that would not produce more organic waste than the plant mass could consume.
> Over time,the buffering capacity that water holds would need to be replenished with GH booster (Calcium, magnesium), or plant's would begin to suffer and fish,, depending on species,,would also feel the effects.
> Heavily planted aquariums that receive few water changes are possible with afore mentioned balanced fish load in proportion to plant mass.(Is a fine balance)
> Heavily planted tank in my view, as well as other's is a tank with no more than fifteen percent of the bottom NOT planted.
> ...


i value my fish....i always calculate adult size into stocking as anyone would.....then i build the tank around the fish...this includes the plants ....substrate...filters....decor....to mimic their natural habitat.


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## Calmwaters (Sep 2, 2009)

I look at it this way. I would not want to live in an enclosed place with my poo and pee so I do not want my fish to live that way either. They may live and not get ill but how do you know they are happy? No matter how hard we try to make a tank natural it is still not natural. In ponds and rivers there are so many factors that we can not recreate in an enclosed tank.


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## rnsheehan21 (Mar 6, 2011)

i have to say that many of your posts have been very interesting with the different angles you guys have come at this topic with. I would agree with many of your points and disagree as well but its good to hear your knowledge, thoughts, and ideas on the matter. to ME these is just a matter of your tanks biology. A fish tank being an enclosed ecosystem should, as in nature, be balanced. This is a goal all of us as aquatic keepers have in common.
...i find its unfortunate that there is not enough information on the internet (that i found) that can support this issue one way or the other. if you find some ( thats not a sales pitch for a product) please share!


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## thinkrevolutionx (Feb 8, 2011)

Water changes mandatory in a planted tank? No.

Helpful? Yes. I'm no scientist - so I can't pretend to know what's going on at the microscopic level - however I will say this.

One of my tanks is an understocked 29 gallon with 2x hob filter and lots of live plants. Post cycle the tank never had anything above 0.0 ammonia nitrate or nitrite, and the PH has stayed the same.

So, the tank is nice and healthy, the fish look good. However, you ever see that film that kind of gathers on the top? Similar to what gathers on puddles? Well, that's not good for the fish, and it's not something you can measure - and it lends itself to the fact that many, many other things are going on in the tank that we aren't aware of. 

That being said, it's obvious clean, fresh water is great for fish - but is it necessary? No, I don't think so.

Helpful? Sure. 

Myself, I don't really believe in water changes on a scheduled basis. What I do is every week or two i'll stir up the substrate and suck whatever pops up, and ill get rid of the film on the top. That process is usually good for dumping a bunch of water out, which I will then replace with fresh water. Boom, water change - but not for the sake of changing the water.

Also, the whole "discus need daily 100% water changes or they will die" thing is just so, so silly. Yes i'm being sarcastic there but really, discus are fish. If the tank is healthy and clean, surprise - they will function just like other fish. I get that they are expensive and people stress, but cmon.


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## Mikaila31 (Dec 18, 2008)

rnsheehan21 said:


> you make a great point but i would say the water you use in water changes has an negative impact too....like mine....its really hard, loaded with calcium, and ph is about 8.4 so its pretty hard to do water changes for me....i'v never had problems with fish health. Usually mineral deficiency results in discolored scales, poor fin structure ect. none of which have ever occurred recently in any of my setups


Once you see those signs you have caused permanent damage. Mineral deficiencies are felt long before they are seen. I've dealt with these personally and no one says, "You don't look good". Only difference is fish can't tell you how they feel. 

You said you had cichlids so I fail to see why a pH of 8.4 is a problem. If tapwater isn't what you want to use then mix in some rainwater. My tap is 7.6 and moderately hard. I strongly disagree about it causing a negative impact. I regularly add Mg and occasionally Ca on top of what comes out of my tap. Your water my not be ideal, but forgoing the addition of important nutrients in a effort to reduce buffering is not the proper way to care for fish. My 3 main tanks all get about 50% weekly no matter what. My closest to "perfect" tank is a 5 gallon paludarium that holds 1 gallon with shrimp. Its maybe 3 years old and has been running very well, no filter, and top off about ever 3 months. Thing is you can't have perfection in a enclosed box. Input must match output or it is not self sufficient. That said tank is not "perfect" though it may on the surface appear to be. It may run just fine for a long time, but will eventually collapse as soon as a SINGLE essential nutrient becomes lacking. From there it will take a very fast nose dive, plants stop growing, uptake stops, waste builds up, and inhabitants get killed. Then the surprised owner explains how the tank was fine for years then "unexplainably" fell apart in a week. 

There is also the long term chronic effect on fish in such a setup. With important ions in low abundance in the water column. There osmoregulatory system will be taxed by such a environment. This costs the fish a great deal of energy to maintain the necessary cellular levels of these ions. The kidneys are overworked and can lead to a shortened life due to organ failure. This also happens quite suddenly and is irreversible, though the onset of it is very slow.

There is a saying in this hobby, "We keep water, fish just happen to live in it." this coincides with the most important rule in fish keeping. For me there is more then enough information to support water changes and none to discourage them.


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## Calmwaters (Sep 2, 2009)

No one said anything about Discus needing a 100% water change but they do need a regular water change because they are delicate fish that cost a lot of money. And unless you have kept them before you honestly in my opinion have no idea what there needs truly are.


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## thinkrevolutionx (Feb 8, 2011)

Calmwaters said:


> No one said anything about Discus needing a 100% water change but they do need a regular water change because they are delicate fish that cost a lot of money. And unless you have kept them before you honestly in my opinion have no idea what there needs truly are.



I have kept discus, and they are no different then any other "Delicate" fish. It's just people being overly cautious having spent a decent chunk of change on a fish - which is fine, but hardly necessary. 

I also clearly said I was being sarcastic about the 100% water change, but this is going off topic.

Mikaila31 has said it best. An isolated ecosystem can operate for years, but one fundamental thing being depleted can cause an entire collapse. This can happen with or without water changes, but they obviously can serve to deter that. In my opinion, avoiding water changes is mostly laziness, or people growing bored of the hobby and not wanting to be bothered.

Also, keep in mind , a sizeable water change can be traumatic for fish as well and needs to be managed correctly. especially if your tap water is not necessarily what you have in your tank water (different PH, temp,hardness etc) and if its not treated properly. My fish generally don't react with stress with large water changes, most of them go swim by it to see whats up, and some swim in it - but i imagine it depends on the fish. I'm not going to dump 10 gallons of water on my angels - but my zebras and female bettas could care less.


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## Mikaila31 (Dec 18, 2008)

odd I dump water on my angels, my tap and tank parameters don't match up exactly. Temp is in the ball park range. Straight from tap to tank. Usually at least 50% a week on that tank. I'm not saying that angels NEED that. However the particular tank they are in requires it for a couple different reasons.


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## 1077 (Apr 16, 2008)

rnsheehan21 said:


> i have to say that many of your posts have been very interesting with the different angles you guys have come at this topic with. I would agree with many of your points and disagree as well but its good to hear your knowledge, thoughts, and ideas on the matter. to ME these is just a matter of your tanks biology. A fish tank being an enclosed ecosystem should, as in nature, be balanced. This is a goal all of us as aquatic keepers have in common.
> ...i find its unfortunate that there is not enough information on the internet (that i found) that can support this issue one way or the other. if you find some ( thats not a sales pitch for a product) please share!


Plenty of information out there on benefit's of water changes and effect's on fishes as well as the result's of few water changes. Keep learning,searching.
You will struggle, to achieve nature's balance in a glass box of water where there are no tides,current's,rains,to take pollution away and where fish cannot swim away to escape it. 
Best one can do is to learn to take care of the water in a closed system. Fish keeping becomes easy after that.


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## 1077 (Apr 16, 2008)

thinkrevolutionx said:


> Water changes mandatory in a planted tank? No.
> 
> Helpful? Yes. I'm no scientist - so I can't pretend to know what's going on at the microscopic level - however I will say this.
> 
> ...


No, regular freshwater to the aquarium along with removing old water is not necessary (as you state above) if you don't mind sickly fish.
Discus you brought up, (not me) are not particularly difficult to care for so long as their needs are met but they do have specific needs.Water changes with Discus are determined by number's of fishes being kept,foods offered,size of fish, adult's/ Juveniles,, and ones expectations with regards to health and appearance.If you don't mind stunted ,sickly,misshaped fish, then that's fine,perform fewer water changes.
Young Discus require large amount of protein rich foods to achieve growth potential which are best offered three or four times a day, as opposed to large single feeding. It is these feedings, and waste produced as a result ,that necessitate the often large daily water changes that folks who care for these fish or raise them for their livlihoods ,perform.
The Discus have high metabolisim's due to warmer water (also a necessity) and foods are quickly digested and pass through the intestines and ultimately into the water. If you want large healthy fish,, frequent water changes are not an option , they are a necessity for this species to remove waste from the fishes enviornment. I would submit that this also applies to all fishes.
It's all about your expectations.


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## Calmwaters (Sep 2, 2009)

Very well put 1077.


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## Byron (Mar 7, 2009)

Mikaila and 1077 have presented good solid facts, and I fully concur with what they've said. I'm just going to take this in a slightly different direction that I hope will further illustrate their points and make it clear that water changes are always beneficial, though the extent (volume and frequency) may be variable depending upon your view.

Fish are the only "pets" we keep in a basically closed system. Dogs, cats, rodents, birds, amphibians (except fully aquatic like Mikaila's fascinating caecilians), reptiles--all these live in air and there is plenty of air moving around all of us. Not so with fish. They depend upon water; and as someone mentioned, we don't keep ourselves in a closed system, nor do we keep these other creatures in closed systems--so why would we expect fish to manage in a closed system? Of course, they won't, and they can't. Mikaila and 1077 have expressed why clear enough.

Our fish come from nature; some are wild caught, some are tank-raised, but their physiological needs are not going to change just because they were bred and raised in an aquarium rather than a stream in Amazonia or wherever. In nature, fish never live in the same water for more than a second. Water is constantly moving past them, or they are moving through water. And the ratio of fish to water volume exceeds by hundreds and thousands anything we could ever provide in an indoor aquarium. If the fish wants to escape something in the water, they swim elsewhere; that option is not available in an aquarium. 

Nitrates are often mentioned as a measurement for water changes. But no fish in nature lives in water with nitrates anywhere close to what we often assume is "safe." I have data for streams in Amazonia where nitrate is so low it is undetectable. A nitrate of even 20ppm may have consequences for this fish long-term.

Fish produce solid waste which gets broken down by bacteria; it is not removed by filters, it remains in the water. Fish produce urine, some a great deal; this stays in the tank, filters do not remove it. Live plants will to some extent handle both of these, provided the fish/plant/water ratio is in balance, which means the fish load is very low. Fish also produce chemicals (as do some plants), called pheromones with fish, allelopathy is the plant equivalent. Filters do not remove these. Only changing the water can. In nature, water changes occur from rain and snow melt.

There is no detrimental effect from a water change. If significant water parameter differences are really an issue, there are ways to deal with that. Having to make the effort to provide what the fish expect to be healthier--and happier--is not something that is optional, or it shouldn't be. If one is going to undertake the keeping of a living creature as a "pet" then one should and must be willing to provide the necessities. Nothing else is defensible.

The extent to which water changes are required depends upon the species and number of fish, the presence of live plants, and the tank volume. Mixing certain species will necessitate larger water changes. Having live plants and a moderate fish load can reduce the volume and frequency of water changes. The reaction of fish to a water change speaks volumes; no one can seriously doubt the benefits.

Earlier one asked for data. In the November and December 2009 issues of TFH there was a 2-part article on water changes that was very educational.

Byron.


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## Cubivore34 (Apr 13, 2011)

*Hypothetically speaking*

hey im new, first post..on any aquarium forum..
im not new with tanks however, and i rarely ever do water changes, and they have always been irregular.
that being said, say you have a 10 gallon tank with a crappy top fin 10 filter at 80 GPH, in a slightly overstocked, densely and diversely planted tank, and then have that water pumped up to a aquaponic grow bed that grows a pretty fair number of plants.. Do yall think thats adequate biological and plant filtration? no im not going into specifics, no time for now. 

oh and i have a 55g,10g,and 3 gallon and the only one i feel i need to do water changes on is the 3 gallon, they are all well planted. and with sand substrate (cept 3 gal)

oh and putting willow branches in your tank does solve green water, as well as starve your plants if left in too long. IMO if nutes are your reason for water changes then willow could be a viable alternative


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## eatmysox (Sep 1, 2010)

Currently I maintain a 25 tank system with a few other display tanks around the house. For all of the display tanks and many of the other tanks I would qualify as moderately to highly planted (there is still room to swim) I Do changes on them weekly in almost all cases. Now when I first started I only cleaned the tanks once a month and everything was healthy. Now that I have started changing the water once a week my fish are not only happy but happily breeding. I have had 8 separate species spawn in the last week alot of them were triggered but the water change. Basically what I am saying is that it all depends on what you want out of your fish keeping experience.


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## AbbeysDad (Mar 28, 2011)

The answer to this question is as simple as looking at nature...the nature, if we're smart, that we try to imitate in aquariums. The streams, rivers, ponds, lakes and oceans receive a constant supply of fresh rain water. This is especially evident in the tropics where it often rains every day.
To think that having a few plants in a tank with fish somehow eliminates the requirement for an on-going supply of fresh water is just not logical.


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## echoman007 (Jan 25, 2020)

I have three established tanks, two beta bowls and never do water changes on the tanks. 1-3 years in age. No live plants. Gravel substrates. I have more than 1inch of fish per gallon, feed my fish whenever I want, (likely over feed them), add filtered tap water when it evaporates which would also probably drive the Forum Community crazy. I don't treat the added water. 

I have Oscar, goldfish and a guppy/neon tetra tanks. My "science" is to "seed" my new tanks with the gravel of my main tank. I might try a new approach with next week's 6th tank by putting a new filter system on my main and stirring up the gravel. I'll then use that filter for the new tank. I may just siphon out some detris too and put it in the new tank.

The deal is, I can achieve nitrogen balance in my tanks with this method and avoid water changes, which I detest. 
I hope I haven't misled you, let me know how it goes.
Gg


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## beaslbob (Oct 17, 2012)

Gee this thread dated back to 2011. LOL.

FWIW what happens with water changes assuming some parameter that is linear and constantly increasing, is that the tank build up that parameter to the point to where the water change removes the build up between water changes. a 1/10 water change builds up to 10 times, a 1/5 the builds up to 5 times, a 1/20 build up to 20 times and so on.

To me it is much more important to slow down the changes as much as possible through (in my case) the use of live plants and peat moss in the substrate. Then just replace water that evaporates.

But that's just me and my .02


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