Water Change

[Freind]

Hi,
I'm wondering how often should I change the water. I used to change 10gl every week for my 80gl tank. Few weeks ago I extend it to 10 days and this time it will be 2 weeks. The water reading is fine.

I'm asking this question as last week I was talking to worker of the local fish seller and he told me that he changes his water at home when needed. I understand its totally wrong, as we should make a schedule. One of his customer told me that she change in a month and one other told me she never change the water. This information make me curious. So can anyone help me how often should I change the water, my tank is 80gl with 8 fishes and no coral.

Thank you,

 

[NSimpkins]

I do a 10% change once a week. More won't hurt. I've heard people that have success with every other week and do a 20%.

Your readings will help guide you. If in 2 weeks you see phosphates and nitrates raising you might want to go every week just to get rid of some of it.

 

[shesacharmer]

I used to change 20% once a week. Then I started slacking off to once every two weeks. Then I ended up with a Cyano problem that started to get out of control. Now I'm changing water twice a week and wish I'd never backed off to begin with. Be careful with backing off too much and then trying to fix a problem you never used to have.

 

[SammyL]

Honetly I think it has more to do with what your bio load is, do you have FOWLR or are you a SPS heavy DT?

I personally change 10% every week, mixed reef.

 

[Dan_P]

Here is a survey I did of forum posts on water changes

http://www.reefcentral.com/forums/showthread.php?t=2451313

Most of those that posted an opinion do water changes at least once a month and between 10 to 30%. The less frequently water is changed, the larger the amount changed.

There is a rationale for changing water but it is an act of faith that you are actually doing the right amount with the right frequency, i.e. you generally cannot tell if water changes make a difference. Try it yourself. What is your rationale for changing water? Can you measure what you are adding/removing. Typically, the answer is "no". Chemical species we can measure are typically not adjusted with water changes.

There is only one case for which you can say with confidence what you are accomplishing and that is a near 100% water change. Then you can say with confidence the impact the water change had on the water chemistry for things we typically cannot measure. You might do a large water change to dilute a toxin or rebalance chemical species.

Routine water changes typically do not cause serious problems, so, the downsides are only cost and time. No two squariums are the same. Pick a quantity of water and frequency of change that is convenient for you or that seems to make your live stock "happy".

 

[gone fishin]

I do believe the bio load has much to do with the WC schedule.

 

[jay.fishman]

Also depends on what is in your tank using up mineral elements and if you are supplementing to replace those.

 

[downbeach]

Here is some worthwhile reading. You'll see that there can be different philosophies on frequency and volumes, but that they all agree that doing WC's are an integral part of a healthy system.
http://reefkeeping.com/issues/2005-10/rhf/index.php
http://www.advancedaquarist.com/2003/10/aaeditorial
http://www.advancedaquarist.com/2004/4/short
http://www.reefs.org/library/article/t_brightbill_wc.html
http://www.wetwebmedia.com/water.htm
http://www.wetwebmedia.com/watchgantart.htm
http://www.wetwebmedia.com/scottsh2ochgart.htm