Water Change Debate

I ran across this on the interwebs and found it to be an interesting question :

"My system went online 05/17/2010 & I have NEVER done a water change.. So, that is well over a year now. I loose 3gal of water a day from evaporation, that my ATO system takes care of. If that is the case, 21gal of fresh RODI water goes into my system every week. That is 84gal a month of new water going into my system. The salt never leaves the system. My clowns, blue-green chromis, & bi-colored angel are over 5 years old & even on my old 29gal I have never done a water change.

It also helps that all my skimmers have been over sized.

IMO water changes can lead to unwanted swings in Salinity, CA, MG, ALK, etc... Granted if there is a major problem & a water change is needed, it is what it is. But if your system is fine, why mess with it. IBM's golden rule "If it's not broken, don't fix it!"





What do you guys think about his/her position on WC's ?

Reef or FWLRO? Will make a difference in a response

I would ask how big is the system and what filtering are they running. I personally think it is dangerous of the person who originally posted this to post stuff like this without in depth explanations with filtering explained and pictures. He could be running an 800g fish only with live rock and chemi pure elite (which advertises no need for water changes) and have a nasty looking system and could have killed off several fish. On the other hand, he could be running biopellets, over skimming and underfeeding with sps and all kinds of stuff. Who knows?! My only point is that I believe it's possible for sure, but I think you have to be more careful with bioload, choose hardy fish and corals and stay religeous with your other tank maintenance.

Still, in general small frequent water changes are a staple of reef keeping. I bet it would be difficult to find a tank of the month that didn't have water changes in it's maintenance. :-)

When it comes to salty...I don't have a clue if it is possible to safely do so.

Since I only have freshwater though, this is the philosophy to which I ascribe. I typically only undertake water changes as part of aquarium cleaning, when encountering water quality issues (usually from something stupid I did), or when having issues with fish illness. I try to keep water changes to a reasonably small amount (<20%) if at all possible.

I also have first hand experience with the effects of poor quality tap water on water changes! I have lived in a few states since growing up here in East Texas and found many other places have all kinds of goodies to look out for. Most of our water systems utilize surface waters (soft) and chlorine treatment. Some of the other areas I have lived utilized well (very hard) water, had chloramines, had high phosphate, had very high iron levels, or a mix of the above. All of which made water changes a pain in the butt to manage. Guess if I had RO water it wouldn't have mattered!

Previous tanks have all been freshwater species from SE Asia and S America in 30G Long or 55G tanks. Much of that time was with undergravel filtration in the aquarium too. Now with external canister filters it is much easier to manage a reasonable stocked and fed freshwater tank.

I now have an overstocked Mbuna tank which will likely pose some bio-load and filtration issues as the fish mature and result in me changing water all the time!

J.Davis wrote:Reef or FWLRO? Will make a difference in a response

+1. Reef tanks need elements replaced that corals deplete over time.

Imo waterchanges are cheap insurance to some serious problems, and are standard in my maintenance routine regardless fw sw fowlr or reef. Everybody likes havin clean underwear lol