RO mixed saltwater same as ro/di water?

Catalina water is filtered natural saltwater, some of the shops here in Phoenix sell it in bulk. Its delivered to the store in a big tank truck.

I would check with the shop and see what they use to mix their synthetic salt water myself, many of the name brand salt mixes are better for captive corals than natural sea water. If thye use RO/DI, will show you a TDS meter reading of 0 or very close to it and their facilities look clean and well maintained thats the route I would go if you are dead set on not buying a RO/DI unit. That would be my first choice hands down since you alone control the water quality that way.

 

WOW...$3.50 per gal. My LFS sells NSW and R/O for $0.50 a gal. Luna

 

Puffer Chick, I'm glad that it looks like you found a solution that will work for you. In order to help others who may find this thread later, I will address your original questions.

• Catalina Saltwater is a "brand" of NSW -- natural salt water (I won't join the debate on the pros and cons of NSW since I live too far from the ocean for it to be an option for me).
• ro mixed saltwater-- the shop runs tap water through a Reverse Osmosis unit and then mixes this RO water with a commercial salt mix (think Instant Ocean or Reef Crystals)
• ro frreshwater-- this is the tap water after it has been run through the RO unit. No salt mix added so this is what you would use to replace evaporative loss (top-off) or if you didn't have your own RO unit you could buy this and mix in your own salt to have saltwater for water changes.
• synthetic saltwater-- water of unspecified quality that has been mixed with a commercial salt mix. I like to think that a reputable LFS would only be using RO water to mix their salt but the name "snythetic saltwater" doesn't rule out the possibility that they are mixing it with plain old tap water. You'd want to verify this.
• RO is revere osmosis
• RO/DI is reverse osmosis water that has then been run through a deinonization resin. Extra step = more expensive, should have fewer impurities than just RO water. Whether this is enough to make a real difference in your tank

BTW the synthetic saltwater that I used when I was a starving student was Richmond City tap water with a few drops of dechlorinator and mixed with Instant Ocean. Salinity 1.025. Please note that I do not recommend this for best results in your reef tank but if your fish already eat better than you do, sometimes you have to cut a few corners:.

 

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