RO vs RODI

RO/DI is reverse osmosis dionized water. It is pure H20--no impurities or additives. For a SW tank, the salt mix will make up for what the DI removes. It's not a matter of being better, it just means that you know everything in the water is what you've added. It's not worth the extra cost, to me, since the RO water will really take care of the big concerns.
 
Sometimes people need to use DI units and special DI units like silicate removes if you have very high levels of things like nitrates, silicates, and phosphates. All of these are pretty difficult for the RO to remove entirely on its own.

You should make sure you use a carbon filter before the RO unit, chlorine will ruin RO units within 6 months or so.
 
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