# RO water?



## str8fancf (Dec 14, 2010)

Hi,

I am new to the saltwater world. Going to start my first SW tank in a few weeks. When doing water changes can you use distilled water instead of RO water? Thanks for the feedback.


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## AZDesertRat (Apr 10, 2009)

Yes.
In order of purity or preference, RO/DI is the best, distilled is second and RO only (as long as it is not labelled as drinking water which is often remineralized so it tastes good) is third. Be careful with bottled RO as it often has minerals put back in for human taste. If you must buy water, avoid vending machines since you are at the mercy of whomever services, or does not service as the case may be, the machines. They are for drinking and not for a reef so may not be what we consider reef quality. Vending machines are not regulated by health agencies so be cautious, they are usually only inspected by Weights and measures for accuracy of the fill amount.

Try and buy bulk RO from a staffed Water & Ice type store if you have them.
I have yet to find a store owner that would not test the conductivity or TDS in front of me since they are pround of what they do. Even in Phoenix with a TDS over 650 they usually get it down to 5-7 TDS with RO only which is pretty good considering.

Bottled distilled from the grocery is usually a good choice for smaller systems. Don't listen to the concerns about copper, copper coils have not been used in stills for years, its all glass or epoxy lined exotic metals now so metals are not an issue.


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## Ben (Nov 6, 2010)

AZDR is correct in everything he says. Having said that, I purchased an RO/DI unit and spent hours installing it and saw ZERO change in my corals, inverts or fish after nearly 3months. I'm religious with the 10-15% weekly water changes, so I'm pretty sure most of the water in my 75g is RO/DI now. Maybe I have above average water quality in my city, maybe my livestock are the chuck norris of livestock, or maybe I'm just lucky. I'm going to continue using it until I run out of filters (3 sets came with the unit) and if I see no change by then, I will discontinue using it.


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