Weeks between water changes?

[Admonition]

So I used to do 20% water changes every week without question; however, now I'm wondering if blind water changes are actually worth doing if your tank's parameters are in check. I understand that water changes help remove Nitrates and add elements like mag, calc, etc via your salt mix. But if my readings for Nitrates are less than 0.2 ppm after two weeks, is it still necessary to do a water change? Couldn't I just keep the ph, mag, calc, alk, etc in check with dosing until my Nitrates reach a level that requires a water change?

 

Or am I just crazy.

[Kijho]

Technically if you're dosing for mag, calc etc. you could get away with it given that your params. stay in check.

 

I personally do my WC every week even though my params are pretty good because I'm not dosing anything. If I was dosing I probably wouldn't need to do a WC every week as long as my params stay good. However, it's still always a good idea to do WC's to keep everything nice and clean, healthy, and to just avoid any problems really. It's a very simple thing that can have a big impact!

 

Give it a try and see how it goes! Just monitor it and if things become bad you know that you'll need to do WC's more often.

[masterbuilder]

I am a believer in water changes. Weekly 15-20% is what seems best for small tanks. I have remind myself that some of the stuff we take out and replace is not really measurable with our crude test kits. So I just don't miss a weekly change.

 

If you want to stretch it out, just go by the look of your tank. Corals, algae, etc. will let you know how its working.

[BulkRate]

Can you? Maybe... as masterbuilder states, it depends on your livestock and the demands placed on your water + dosing schedule.

 

I know that in my tank the corals look fine if I skip the bi-weekly changes for a week or two, but that almost everything gets ticked off for a few hours to a day if I don't resume the change schedule more gradually than usual. You're doing more than replacing depleted trace elements or removing waste buildup when you change water - you're maintaining the stability of the system, including all the other stuff we can't test for, too.

 

The longer I keep a reef tank the more I feel that change is the number one killer. Good number/bad number on a given parameter almost matters less than whether it changed significantly in a short period of time - for better or worse.

[doppelganger]

I've gone 3-4 weeks without doing water changes before. That being said, I do dose.

 

I'm a bigger fan of doing smaller water changes a little bit more often if I have to. This is only because I'm lazy though. It really depends what works best for you because if I do small water changes more often it literally takes me like 2 or 3 min to change out 2 gallons of water (34G tank). I don't worry about the temp of the water, or even if the salinity matches perfectly because it's such a small amount of volume it doesn't change things much if it's off by a little.

 

Keep in mind that I can only do this because I don't need to export a huge amount of nitrates. Thus the small water changes are just for replenishing some trace elements and stuff.

 

That's just me tho and it works for my system. Obviously it'll be different for anyone but yes, fewer water changes can be done if your parameters stay in check and everything is still responding well.

[pgrVII]

I've had good luck changing 5 gallons out of 28 gallon (more like 24 gallons really) every 3-4 weeks bow that the tank is a year old. I was doing one every other week for the first 4 or 5 months,but once the system got steady backed them off. Seems to work and everyone stays happy.