# How else do water changes benefit the tank?



## Oto Guy (Jan 3, 2014)

Oxygen and PH levels can drop if there are too many nitrates, nitrites, ammonia. It can also hurt the fish and create stress for them.


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## HUNTER (Sep 4, 2012)

It's an enclosed system and water change is the only way to refresh the water. If you think you're taking out some of the important nutrients like ferts, just replace them after water change, at least you know you're getting rid of some bad stuff.


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## NYCaqua (Dec 26, 2013)

To reduce excess nutrients in the system if you are among those who dose the tank with many ferts. As well as reduce possibilities of the buildup of excess nitrates.


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## DarkCobra (Jun 22, 2004)

Without any water changes, water parameters will progressively drift further from your tapwater (or other water source). This may not cause an issue by itself, as fish and plants can often adapt to the change, since it's slow.

The problem comes when you finally do a water change. And you may be _forced_ into doing a large change. Because a medication requires it, you've had a tank leak, Windex overspray got in the tank, a child dumped in too much food, or numerous other unforeseeable reasons. Large, sudden changes in water parameters can be a massive shock to all inhabitants.

So without water changes to keep your tank water acceptably close to replacement water, sooner or later you will find yourself in a situation you have no way out of without losses.

Water changes need not be 50% or weekly, depending on the situation and your personal preferences. But they should still be done on some regular basis.


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## Django (Jun 13, 2012)

I hadn't thought about that. I like your message because it seems well thought-out. Thanks to everyone who has replied so far


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## THE V (Nov 17, 2011)

Water changes are needed if you add anything to the tank. Food, fertilizer, and/or tap water to replace evaporation. The less amount of these you add the lower the percentage of water changes you need to do. 

Some low tech setups that only top off with tap water only need a water change every 6 months.

If the tank is never fertilized, fed and only topped off with distilled water they can go decades without issue. 

I'm debating doing one of these setups for my office. There is periods of the year where I might make it too my desk once a month.


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## PlantedRich (Jul 21, 2010)

There are lots of things in the water which might build up. Lets take one that is simple to see. Limestone is often one of the minerals in the water. When water evaporates, the limestone is left. Like the scum on a tea kettle? If we don't remove this while still suspended in the water, it gradually would get thicker and thicker. At some point that's too much. Just one item of many we don't want creeping higher. Each water source will have different things but same general problem.


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## THE V (Nov 17, 2011)

^If you replace the evaporated water with distilled\RO water there is very little if anything building up. If you replace it with tap water you are absolutely correct.


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## Django (Jun 13, 2012)

You can measure the dissolved mineral buildup with a GH test I believe. I have been doing that weekly before my water change. I have a GH of around 5 dGH.

I think also that the softer the tap water the longer dissolved minerals will take to build up, especially with a 50% water change. But my fish seem less happy if, for example, I don't get to the water change one week.

One last point - as water evaporates before top-off, dissolved minerals increase to some degree - probably not that significant.


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## plantbrain (Dec 15, 2003)

Django said:


> You can measure the dissolved mineral buildup with a GH test I believe. I have been doing that weekly before my water change. I have a GH of around 5 dGH.
> 
> I think also that the softer the tap water the longer dissolved minerals will take to build up, especially with a 50% water change. But my fish seem less happy if, for example, I don't get to the water change one week.
> 
> One last point - as water evaporates before top-off, dissolved minerals increase to some degree - probably not that significant.


Look at it from a pure observational standpoint:

Fish happier= 1 or 2X a week large water change
Plants happier, grow better, cleaner, less chance of algae- water changes 1-2x a week
New tank start ups: large water change every 3rd day= very little issues with new tank or algae, very healthy plant growth.

Obviously, adding ferts after each change and then a bit more 1-2x more during the week will help. This way the ferts never get too high, nor ever run out.

These re much simpler habits and easier to rule things out than any test kit array with all the various nutrients. That can be done, but it's a PITA. Water changes and dosing much easier from a practical standpoint for 98% of the hobbyists.

Once things are growing and doing very very well, now you can slowly taper off and see if say 1x a week or 2x a month water changes works well. I do 2x a week on one tank I arden a lot and then only once a month on another that I do not. A non CO2 tank like DW suggest? These do not need much, any since they really are not growing that fast compared to CO2 enriched tanks. 
There are some trade offs with non CO2, they are not equivalent to CO2 methods and should not be viewed as such. You have far more options with CO2 enrichment and much more gardening ability.

It's bad advice to sell a newbie on no water changes or few and then they add only a few plants, lots of fish and high light often, and no CO2. More experienced folks, sure. They can and should try non CO2 methods. 
But it's not going to meet success for many goals that aquarist have. 
Start with that, then you can figure out the best management method for your goal.

No one method will be all things to all people.


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## Rooster (Apr 3, 2006)

unless that tank is sealed, as in gas tight, then you are collecting airborne contaminants... dust, mould spores, air freshener, diesel fumes from traffic..... the list is endless, you HAVE to replace water imho

Sent using Tapatalk from my ZX81


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## Jack Gilvey (Jun 16, 2008)

I think the bottom line is that folks who do water changes tend to have better, healthier tanks. 



Rooster said:


> unless that tank is sealed, as in gas tight, then you are collecting airborne contaminants... dust, mould spores, air freshener, diesel fumes from traffic..... the list is endless, you HAVE to replace water imho


 This is something that's rarely addressed. If you smell it, it's getting in your tank. I do about 75% weekly in the tank in my daughter's room and this is not a minor reason.


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## Aquaticus (Jan 7, 2013)

I've gone several months without a water change on my 75 gallon, densely planted, low tech tank with a lot of fish that are fed regularly. I think it helps that I have a lot of fast growing plants (several hygros) and floaters. A large swordplant easily takes up a third of the tank as well. No algae thanks to photoperiod management and otos and shrimp. That being said, the corys really spawned like crazy after the last water change!


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## Exotics (Jan 23, 2014)

Just a question on water changes. How long must I wait, after I added the dechlorinator, to add the water the tank?


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## creekbottom (Apr 5, 2012)

I use Prime, and add it to the tank as I add water from the hose.


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## Exotics (Jan 23, 2014)

Do you treat the amount being replaced or for the whole tank?


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## plantbrain (Dec 15, 2003)

Aquaticus said:


> I've gone several months without a water change on my 75 gallon, densely planted, low tech tank with a lot of fish that are fed regularly. I think it helps that I have a lot of fast growing plants (several hygros) and floaters. A large swordplant easily takes up a third of the tank as well. No algae thanks to photoperiod management and otos and shrimp. That being said, the corys really spawned like crazy after the last water change!


This works well with this type of tank if you use CO2:

http://s171.photobucket.com/user/plantbrain/media/Buce1-7_zps53920a17.jpg.html?sort=6&o=22

But will not work with this type of tank:



And if you dislike CO2, well then it'll work even better with a tank like this:




Water changes can be done a lot more frequently on each of these tanks, but you gain less from doing them so frequently at some point, the lower energy, lower CO2 type tanks with less light, easier plants, more routine fish feeding etc, they will not require as much generally.

As far as all those other thing that end up in the water, there'd bacteria that will process most of those and plants will take up those by products, you trim, then there's the export of those waste products.

It tends to help to have several comparative tanks to illustrate why more or less frequent water changes are needed and then see what's good/the best advice for new folks. 

Generally, more water changes= better and certainly the best advice to tell a new aquarist. Like yourself, I and most folks have neglected to do water changes, the tanks generally did not die and go crazy with algae, but in some cases, the tank did. More light, CO2 and more weedy stem plants caused most trouble.


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## PlantedRich (Jul 21, 2010)

The chlorine in the tank might be compared to a sunburn. It is like too much hot sun for too long is really bad. Less time or weaker sun is less bad. When you add the dechlor product, it takes a small time for the chemicals to meet/find each other. If you change 50% of the tank water with chlorinated water, that is still not too large PPM but some burning. If you add the dechlor right away, the damage will be less. I find it better to add the dechlor product before the new water but it is not a really scary thing either way for many fish.


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## Exotics (Jan 23, 2014)

PlantedRich said:


> The chlorine in the tank might be compared to a sunburn. It is like too much hot sun for too long is really bad. Less time or weaker sun is less bad. When you add the dechlor product, it takes a small time for the chemicals to meet/find each other. If you change 50% of the tank water with chlorinated water, that is still not too large PPM but some burning. If you add the dechlor right away, the damage will be less. I find it better to add the dechlor product before the new water but it is not a really scary thing either way for many fish.


Thanks, I did my first water change today and was wandering about that. I added the dechlorinator to each bucket of water before adding it to the tank. Glad to hear I can use a hose next time, it took me forever doing it like that.


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## Aquaticus (Jan 7, 2013)

plantbrain said:


> This works well with this type of tank ...But will not work with this type of tank:


No argument from me there. While I love the look of a well maintained and manicured high tech tank, it is not what I aspire to right now. I spend a lot of time maintaining my 20 fish tanks (mostly breeding for my club's BAP program), so I find my low tech 75 to be very rewarding. The breeding tanks in my fish room get water changes at least once a week, but the 75 upstairs gets it when I get a free moment every couple of months. It works for me, and the plants and fish are thriving. It isn't the clearest tank (no filter, just a powerhead), and it is a little wild (infrequent, heavy trimming), but that is OK.  I also agree that telling new hobbyists to do frequent water changes is a good idea.

Eric


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## tgenega (Dec 3, 2013)

Ok - so the benefit of weekly water changes decreases as a low-energy tank stabilizes... but is there still some benefit?... or do weekly water changes actually become detrimental at some point in the evolution of a low-energy tank?


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## Aquaticus (Jan 7, 2013)

Sure, there is always some benefit, such as the addition of trace elements from your tap water (if you aren't adding them in other ways). That I can think of, water changes would only be detrimental if the water were significantly different than your tank water and you changed too much of it at once.


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## Aquatic Delight (Mar 2, 2012)

heres how i explain this... 

lock yourself in a room (of any size) that has some plants in it, and food. then don't open a door or window, don't leave to go to the bathroom.

after a few weeks tell us how you feel.


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## tgenega (Dec 3, 2013)

Makes sense to me... yet I've seen several posts to the effect that an algae problem was solved by reducing water changes... ??


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## plantbrain (Dec 15, 2003)

Aquaticus said:


> No argument from me there. While I love the look of a well maintained and manicured high tech tank, it is not what I aspire to right now. I spend a lot of time maintaining my 20 fish tanks (mostly breeding for my club's BAP program), so I find my low tech 75 to be very rewarding. The breeding tanks in my fish room get water changes at least once a week, but the 75 upstairs gets it when I get a free moment every couple of months. It works for me, and the plants and fish are thriving. It isn't the clearest tank (no filter, just a powerhead), and it is a little wild (infrequent, heavy trimming), but that is OK.  I also agree that telling new hobbyists to do frequent water changes is a good idea.
> 
> Eric


Yep, you have no business messing with the 120 Gallon like I have above.
Non CO2 methods are the best management choice for you. So focus strongly on those methods, they will serve you and the livestock much much better than my weed choked cess pool.


MTS is a bad disease. 

Some info on non CO2:
http://www.barrreport.com/showthread.php/2817-Non-CO2-methods
http://www.plantedtank.net/forums/showthread.php?t=82524
http://www.aquaticquotient.com/forum/showthread.php/13623-Tom-Barr-s-Non-CO2-method


Diana Walstad's book is good and useful. 
I actually like a nice looking scape to go with my methods though.


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## plantbrain (Dec 15, 2003)

tgenega said:


> Ok - so the benefit of weekly water changes decreases as a low-energy tank stabilizes... but is there still some benefit?... or do weekly water changes actually become detrimental at some point in the evolution of a low-energy tank?


I'd say they offer little for the low energy tank, which....is the point of a low energy tank, you do not want to put a lot of effort into keeping up with it, if you do, then get the CO2 gas and garden.

Who has a goal of putting a lot of labor into a low energy low labor tank?


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## plantbrain (Dec 15, 2003)

Aquatic Delight said:


> heres how i explain this...
> 
> lock yourself in a room (of any size) that has some plants in it, and food. then don't open a door or window, don't leave to go to the bathroom.
> 
> after a few weeks tell us how you feel.


If the room is very big and there's a lot of plants and food being produced at a decent rate, enough remineralization of the waste and uptake by plants........then a very very long time. 

But if the room is small and lot of plants still, but remineralization cannot keep up and organic matter builds up, fers get all whacked out.......not likely. Most have this situation and not the non CO2 approach above.


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