How fast/much can you safely do water changes?

[Toxic Slurpee]

Long story short, I recently found out that my old RO/DI unit has been underperforming for a while and I've been putting sub-standard water into my tank.

My new RO/DI unit comes in tomorrow. The goal would be to ultimately change out 100% of the bad water in my tank as quickly & safe as possible.

Is something like a 10-20% WC every few days OK? (100 gallon tank)

 

[aleonn]

Do you notice any problems with coral or fish health and behavior? If not, I'd just gradually change out the water.

 

[pscott99]

+1

What was the TDS ? I see no reason to panic if everthing is looking good. Your skimmer and GAC probably cleaned it up.

 

[ek9vboi]

I'm curious to see what your TDS reading was.

 

[JHawlz9989]

I have done 10% every three days on my 20g, with no adverse effects. I did, however, let the water mix a bit longer than I usually do.

Josh

 

[Randy Holmes-Farley]

I wouldn't do any special changes. Many of the things that might have gotten in are not easily removed even with a 100% water change since they can stick to rocks and sand and organic matter (including copper and phosphate, for example).

 

[bertoni]

I wouldn't bother with a bunch of water changes, either, but 10% a day should be low-stress if you're worried or any animals are having problems.

 

[Chris Lakies]

Make sure u let the new batch mix 24 hrs. I found that trying to add freshly mixed water could cause negative reactions. I also add the new water to the sump and let it pump in slowly to the main tank.