Water Changes

[joeman]

Do you think it is feasible to create a system where water changes are not required?
Assume a very low bio load, plenty of live rock sitting on a sand bed and a sump + refugium + skimmer + denitrator + UV sterlizer...
One long standing reason for changing water has been to dilute (reduce) the nitrates that accumulate from anyting that was not caught by the skimmer then overwhelmed the anaerobic bacteria in the live rock etc...
Well with the addition of a dinatrator it becomes possible to maintain nitrates at zero.
I also believe it is possible to maintain a similar level of control over phostphates etc.
So the next reason I have heard is that "we just don't know what is important in water = additives alone are not sufficient", but this argument just does not stand, for I use RO/DI water (essentially just H2O) and add synthetic salt mix - what is the difference between that & topping up with RO/DI water + additives to maintain target levels?
It would be great to get people's thoughts on this as I just can't get to a satisfactory answer myself. :confused:

[dcombs44]

Experiment:

Set up 2 tanks of the same nature with the same salt mix. Try your no water change method on one and weekly water changes on the other. Do this for a year or so, and compare the results.

I know people that haven't do very few water changes with some success, but it seems like the great tanks always seem to be frequent water changers.

[SlowCobra]

The cost in additives to offset the essential elements that get used(Ca, Mag, Iodine, etc) would probably not offset the cost of the salt.

[joeman]

Thanks for your replies:
At this point cost isn't really part of it - I'm just trying to understand if there is still the need to change water and what benfits it brings.
Regarding the suggested experiment, I take it that means nobody really knows or has run this expriment? I might just give it a try and publish results in about 12 mnths. What parameters would you suggest I monitor / record?