how often?

[cathy]

We are thinking of changing our practice, and would like your opinions! I have heard and read about two approaches to water changes: 1x month, approx 25%; and 1x week, approx 5-10%.
Our tank is 5 months old and regular testing shows that all our parameters are where they should be. Daily I do a little "lite housekeeping" eg, removal of excess algae from the glass, gentle disturbance of the crushed coral if there is algae growth there. Not enough to make a cloud, just enough to disrupt anything that's getting a foothold. Early on we did have the expected bloom; now what I remove daily is minimal. We have been doing monthly water changes, changing necessary filter components 2 weeks after.
Recently we added some inverts. (see post ?over my head?) Everybody is looking really happy today and I am starting to rethink our water change, which is due at the end of the week. Would it be more advisable at this point to start doing the smaller weekly change? In a way that almost seems easier anyways. Any suggestions are welcome.

[VoodooChild]

I like smaller, frequent changes to try and maintain parameter stability. I usually shoot for 2.5gal. (in a 30 gal.) every week. I figure the tank actually is holding closer to 20-24 gallons after displacement, so that means somewhere aroudn 10% a week.

[OrionGirl]

We do 25% changes every other week, on about 180 gallons of water (call it a 55 gallon water change). What it comes down to it that you should do the changes that work for you, and keep the parameters inline with a healthy tank. Smaller tanks require more work, since they can go off keel more rapidly than a larger system. There are advantages to regular, small changes, especially if you skim--regular changes replace the trace elements, that will otherwise be depleted.

[mogurnda]

I would do whatever is easiest to keep up. The main goals of water changes are nutrient export and trace element replenishment, and either schedule should be OK.
I have been doing 20% weekly changes on the 20, and the corals perk right up. It's a bit extreme, I know, but I have a lot of life in the tank, and I have been worried about chemical warfare from the softies.
My suggestion is to try a new regime, and change it if it becomes a pain or your nitrate starts to climb.

[cathy]

thanks all! I think what I am going to try is to change 4 to 5 gallons, every other week. We have a 46gal, so accounting for the displacement from the live rock, that's probably in the 10 to 15 % range. I checked with our Lfs too. The Lfs, who is familiar with our paramenters (they test our water before we buy stuff) suggested the every other week routine for now. I will let you know how my stuff does! Thank goodness I am not scheduled to work another weekend in the near future.......I wil also be able to keep better track of my husband and prevent any "surprise" purchases!!!!

[VoodooChild]

I forgot to mention that I don't skim and that's the reason behind weekly changes. Otherwise it'd be every other week.

[cathy]

that is a helpful add - on - makes sense!