Maximum Percent Water Change Out?

sen5241b · #1 October 8th, 2008, 08:30 PM

Not enough water changes and water quality goes bad. Too great a percent is changed out during a routine water change and beneficial bacteria may be reduced too low. So, what is the maximum safe water change out? 50%?

reeffreak · #2 October 8th, 2008, 08:52 PM

It more the shock from water chemistry difference(pH,temp,salinity etc) than the beneficial bacteria.99% of the bacteria post cycle is coating the rocks,sand,glass and other equipment.They are not removed during a waterchange.Yes,50% is the most I hear the most.Although,I prefer smaller 10-25%.Doing 50% at once,I feel will expose to many of my corals to air for maybe too long.

ccCapt · #3 October 8th, 2008, 09:59 PM

I agree with reeffreak. 50% would be about the max I would do, but you can do a 50% change every 2-3 days.

ZOOT098 · #4 October 8th, 2008, 10:44 PM

i do 10% once a week and all parameters have been great
only time i do more is if there is a problem
the most ive ever been advised to change at once is 50%
but not as regular maintenance

yote · #5 October 8th, 2008, 10:56 PM

The most I've ever changed at once was a little over 75%.But that was on my first salty tank and I wouldnt attempt it now.
I'd even be a little skiddish about doing 50% now.

dustin_P74 · #6 October 8th, 2008, 11:10 PM

i wouldnt do a 50% water change regularly but if emergency's arose thats as much as i would do at one time

Rcpilot · #7 October 9th, 2008, 01:43 AM

I overdosed my nano with buffer and the water turned milky white instantly.

I did about 30 water changes 3g each over the course of 24hrs. Thats like 2000%

Didn't hurt a thing. The tank would have been worse off if I HADN'T done that.

ccCapt · #8 October 9th, 2008, 01:58 AM

Quote:

I overdosed my nano with buffer and the water turned milky white instantly.

What happened there was the calcium precipitated out of solution. As long as there was no pH spike up or down, nothng would be affected anyway. In 24 hrs or less all the precipitate would settle. You would then have to test your ca, alk and mag to get the levels back up, since it's all calcium carbonate now and it won't re-dissolve.

This is somewhat common for SPS keepers who try to push their levels to the max and get them all out of whack.

JAG107 · #9 October 9th, 2008, 02:42 AM

A little OT--My neighbor told me when he moved in 3 yrs ago he kept 50% of his water and carried the tank in, said "I was too lazy to go get salt water from the LFS" and dumped 50% FRESH TAP WATER in and wondered why everything died within a week. HE also claimed to have 8 yrs experience with saltwater. hmm.

**Bifferwine** · #10 October 9th, 2008, 02:44 AM

I would only do 50% in an emergency situation. Any time else, I'd stick with 10% to 30%.

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