# Using RO/DI water to top off?



## Chrisphungg (Oct 8, 2012)

Is it safe to use RO/DI water to top off the evaporated water in my SW aquarium? The RO/DI water has a pH of 5.8. Do I have to increase the pH before adding it into my aquarium?


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## dino (Aug 29, 2011)

I top off with it and dont adjust anything


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## The Guy (Nov 26, 2010)

dino said:


> I top off with it and dont adjust anything


+1 to this


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## effox (Apr 21, 2010)

Since you're replacing evaporated water, it wouldn't impact the ph in the tank. If it was a higher volume water change it would be measurable I'm sure.


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## JTang (Apr 21, 2010)

I use RO water to top off as well. Only thing I add is Seachem Reef Carbonate (100 ml / 5 gal of water) to bring the low kH up.


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