The water change myth

I felt it was time to debunk the myth about water changes. From this and the other forums I am a member, I am amazed how many people suggest a water change to accomplish everything from lowering Nitrates to curing a Coral. The article you will read will put to rest the idea that water changes can accomplish these things, or it should if you keep an open mind to the actual physical occurrence that happens when you do a water change. Although the article is focused on why water changes do not effectively keep nitrates under controll, let alone eliminate them, you will see the minimal effect they have and why a water change will not cure anything in and of itself. Happy reef keeping!
Aquarium Information - Water change and nitrates

 

to claim water changes doesn't remove nitrates, nitrites, and ammonia is illogical.
even in the example nitrates were being removed. 9 units is alot better then 40 with out water changes.
if following that example eventually the nitrates will build up and create old tank syndrome. just think if after a month the 9 nitrates could be reduced even farther buy another 50% water change the next day, giving you 5 nitrates. in effect buy doing 50% percent a couple days in a row every so often you could keep you nitrates to minimal levels forever.

so as long as you test your water every so often and adjust you water change schedule accordingly you could prevent the build up of nitrates

the reason you do water changes in SW is to replace trace and macro elements.

 

EDIT: retracting my statement...

 

By the way, here is an excellent article on water changes. There's also a section on water changes for nitrate control that explains more clearly what I was trying to say.

Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com

 

Well, I wouldn't be so sure about that. Restoration of proper ion balance is probably the most important function of water change. Since most of the reef tanks are closed systems they tend to accumulate lost of "unused ions". To be more specific, sulphonates, chlorides, sodium, potasium and related. These ions are not metabolized directly, they obviously have their function in living organisms. However, accumulated tend to create hyperosmotic environment that simply step-by-step eliminates bacteria and other susceptible microrganisms. Proof ?! The great Dead Sea. Potassium and sodium salts are almost always soluble what makes them osmotically active! The only way to get rid of these salts is to literally remove them with water and finally decrease their content by dilution!

Enjoy the beauty of science

 

The OP is forgetting that other methods are the primary tools for removal of fish bioload and nitrates, that being the protein skimmer, denitrator coil, and mechanical/bio filters. Without a protein skimmer, the bioload would definitely build up week after week w/o any water changes.
But when you add the correctly sized coiled denitrator, skimmer, and filters, to a tank that isn't "over-stocked", then you got no problems with nitrates.
Water changes are still the best quick solution for dilution!

 

To say water changes don't change the level of nitrates is to say taking water from a bottle doesn't change the amount of water in the bottle.

When you take a portion of nitrate filled water out of a tank, and then add water without nitrates to the tank, naturally the nitrate level in the tank is going to be lower. It's logic, not science. Well...I guess it's science too...but you know what I mean.

Along with the filters and water treatment methods listed by Bogie, one of THE BEST ways to reduce or eliminate nitrates is to have a refugium setup. When you have fish and inverts in an aquarium, but no plant matter, you're creating a one way street for nitrates. They build up and up and up, but there's nothing to get rid of them. Add corals, and various types of plant life and algae found in a refuge, and the nitrates will be used up by the "plant" life, making it a two way street and making it much easier to handle nitrates.

Of course, it is easily possible to control nitrates with regular water changes and a proper bioload if you do not have a fuge. I would know, because that's what I do. Nitrates have never been over 10 in our aquarium, even after cycling.

my .2

 

did anybody actually read the article, i did. re-read it, then skim back through your replies to make sense of whats written.

 

theres more to keeping a reef than controling nitrates.i just can't buy into not changing water.i can see and smell when the water needs changed without even testing.i add food to the tank that the fish and corals eat and then expel as waste into the water.my filters can only delay the amount of time between water changes temporarily.those same filters don't just take waste out,they also take needed stuff out along with the waste.now,you can add things like magnesium and calcium back into the tank,but you'll never get it all just right.i tried it.i could'nt get everything balanced just right and it all swung wildly out of control.the mag,calciun,and ph went nuts.i lost $150 in coral.never again.my skimmer takes elements out,my chaetto,my corals even take stuff from the water,and even though things like calcium are still in the tank,they are'nt in the water colum once the coral consumes it.not unless the coral dies,which it will if you don't change some water at some point.even your top off water is a factor.my top off water has 40-65 ppm tds.in time without water changes it will add up.of course i'm just a lower class fellow with a mostly softy tank and a loss of a $40 coral or fish is a bad blow to my hobby.its taken me 2 yrs of careful saving and alot of do it yourself to get just my 55 gallon fully stocked and stable.the max i can go is 10 wks before its change water or watch it all die.

 

The point of the article is not that water changes are not needed or serve no function! It just simply illustrates that if your system is producing more nitrates than are being consumed then doing water changes will not be a good long term solution for controlling your nitrate problem… or am I missing something?