why do water changes?

[Matthew Morrison]

If fuge and gfo remove phosphorus. If carbon removes what carbon removes. If skimmer removes all the gunk and particals. If calcium, magnesium, alk, major, and minor trace elements are added. If cycled tank removes all ammonia nitrite and nitrate. Then why should i do water changes?
this is not an argument. This is a legit question. Im willing to do water changes. I just don't understand why i am doing them.

 

[lapin]

If fuge and gfo remove phosphorus. .

Maybe some but not all of it unless you have low p04 or a lot of gfo.

If carbon removes what carbon removes. .

Let say it removes some chemicals

If skimmer removes all the gunk and particals. .

Maybe 30 % if your lucky

If calcium, magnesium, alk, major, and minor trace elements are added. .

Why would you not add all the elements needed by doing a water change

If cycled tank removes all ammonia nitrite and nitrate. .

A cycled tank will never remove all nitrate unless it is a special set up to covert it to some other substance.

Then why should i do water changes?
this is not an argument. This is a legit question. Im willing to do water changes. I just don't understand why i am doing them.

I do them because its the easiest way to maintain stability in my tank.
You can look up "no water change tanks" and see what their opinions are.

 

[jda]

I do them because they are cheap and easy. Think about it... How much will you spend on additives and GFO? I can get a 50g bag of IO for about $8-9 and RO for say $1.00 with water and filter costs. $10 a month? I get the "too lazy to change water argument" (although I think that this makes you a bad keeper if laziness if your excuse), but if one of the best known methodologies to keep a tank health is $10 a month, then what is the downside? Some people just think too much or work too hard.

Also, do not discount the time with your tank. Most of the truly "maintenance free" setups that you see are short lived. The people who do their maintenance typically have longer lasting tanks since they are around to see stuff.

Some tanks can handle all the nitrate, but they have to be mature and otherwise heatlhy. ...as P starts to rise, the bacteria can suffer rock and sand get "clogged up" and the water cannot get into the zones that were once anxoic to have the nitrate convereted into nitrogen gas. In short, healthy tanks can process NO3 into N gas, but it takes work for them to be able to do so.

*I am not counting perhaps the big-4 which usually need supplemented (carbonate, calcium, mag, strontium). This is a given since t

 

[ca1ore]

There certainly are approaches that eschew water changes ..... Triton as the most obvious current example. I've not done it so cannot judge whether it sustains in the long run. I've been of the view for some time now that a calcium reactor can be useful in reducing the necessity of water changes, as long as you have varied nutrient export mechanisms; but I've not done anything that even approaches a valid science experiment, just anecdotes.

 

[mcarroll]

If fuge and gfo remove phosphorus. If carbon removes what carbon removes. If skimmer removes all the gunk and particals. If calcium, magnesium, alk, major, and minor trace elements are added. If cycled tank removes all ammonia nitrite and nitrate. Then why should i do water changes?
this is not an argument. This is a legit question. Im willing to do water changes. I just don't understand why i am doing them.

It's useful to look at nature when you have that kind of question. Ask what you're emulating.

Water changes are massive in nature, and pretty much the norm. But the norm is not universal.

Various reef environments have much more moderate water exchange with the open ocean.

Which environment are you attempting to recreate?

 

[Matthew Morrison]

It's useful to look at nature when you have that kind of question. Ask what you're emulating.

Water changes are massive in nature, and pretty much the norm. But the norm is not universal.

Various reef environments have much more moderate water exchange with the open ocean.

Which environment are you attempting to recreate?

enviroment that grows and maintains coral

 

[mcarroll]

FWIW, I've almost split the difference between water changes and no-water changes. All I can say is that both work, as long as you're on your game. I don't think I'd start someone off doing no water changes though.

 

[mcarroll]

enviroment that grows and maintains coral

Do you have any books on reefing so far that I could refer to?

Hang on...

 

[Matthew Morrison]

i guess what im trying to understand is what is the reason for water changes? just a removal of nutrients and introduction of elements?

 

[Matthew Morrison]

if those nutrients are removed and introduced without water changes then what else is the reason for water changes?

 

[jda]

All of those things... as well as exporting the unknown and untestable and replacing it with more pure stuff.

I have heard it compared to just opening some windows on a nice day... even the best air purification system is no substitute for fresh air. This is not a 100% equivalency, but close.

 

[Sallstrom]

This discussion usually comes down to if it's necessary to remove "the unknown" or not.
The answer is unknown

 

[JimFuller]

A few things to think about are the trace elements. Iron, strontium, iodine, and many others. A water change covers a lot of chemistry. I do them just to help keep stuff I can not test for up to snuff.

 

[WVNed]

A few things to think about are the trace elements. Iron, strontium, iodine, and many others. A water change covers a lot of chemistry. I do them just to help keep stuff I can not test for up to snuff.

and because we do water changes we do not have to test for them.

Reef dialysis.

 

[Dumaurier7]

I’ve never done a water change in almost 2 years!

 

[Mortie31]

Water changes can also dilute major issues, such as a rusting MO40 wetside, unless you are doing very regular ICP tests with your no water change system, it will likely be to late before you notice the difference, I believe regular water changes give you a bit of a buffer to this type of things as well as adding in alot of the trace elements in a relatively balanced manner, again something that is difficult unless you are doing regular ICP tests, which cost so much you might as well do bigger more frequent water changes....and this in turn can further reduce the amount of trace elements you need to add as well.. all of this is from my experience trying triton and no water changes... I now do 24 Water changes a day, all automatically.. but then again people like GlennF who uses the DSR system would completely disagree with me

 

[HB AL]

For my 1st 25 years i did weekly water changes, in the last 5 years ive slowly gone away from them, to the point now of not doing any. My current tank i started as a fowlr about 2.5 years ago, wanted to keep it simple. Well that didnt last for long as i found myself everytime i visited my lfs's adding a small frag here and a small frag there, no specific species, if i liked it i put it in the tank. About a year in I had all the fish stocked i wanted plus i was way maxed out with 15 fish. Today they are still going strong. Fast forward to today and my tank is a full blown cluster **** of all types of corals. Sure some corals could have better coloration or faster growth rates, but for me its good enough and in my case the fish are more important, but the frags i cut off i trade in to my lfs for free fish food. Now go back in time I probably would not have been successful growing corals without frequent water changes. With all the products that are out there now it makes it possible to have a successful tank without doing water changes. Heres a couple pics i just took showing that not doing water changes can have a successful outcome although i would not suggest it to someone just starting out in the hobby.

 

[beaslbob]

If fuge and gfo remove phosphorus. If carbon removes what carbon removes. If skimmer removes all the gunk and particals. If calcium, magnesium, alk, major, and minor trace elements are added. If cycled tank removes all ammonia nitrite and nitrate. Then why should i do water changes?
this is not an argument. This is a legit question. Im willing to do water changes. I just don't understand why i am doing them.

simple answer is you shouldn't. It's much better to balance out the system so water changes are unnecessary and can only result is tank degrading.

What happens with water changes is the tank eventually winds up to where the stuff removed by the water changes is equal to the total change between water changes. For instance if nitrates are increasing at say 1ppm/day and you do a 1/5 water change every 10 days. the nitrates will be 50ppm just before the water change. In equation form there is 1ppm*10=10 PPM nitrate increase between water changes. So the 1/5 water change has to remove 10ppm nitrates. So 10ppm/(1/5)=50. After the water change you have 40ppm which builds up to 50ppm for the next water change.

By contrast using a macro algae fuge or algae turf scrubber you just have 0 ppm all the time.

my .02

 

[Cory]

Waterchanges are just to remove things we dont usually test for. However sometimes water changes add that which we are trying to remove!

 

[jda]

There is a lot of misinformation in this thread... nitrate can and should say near zero even without water changes or a fuge... bacteria can take this of this in an established tank. Phosphate is harder where the aragonite will bind a ton and act as a buffer in low concentrations and a reservoir in large concentrations. Phosphate needs to be removed by fuge, GFO or water changes, unlike nitrate which does not have to be.