whatever, there is a way to do it.
Edit: http://www.atlantareefclub.org/forums/showthread.php?t=48306&highlight=salinity">http://www.atlantareefclub.org/forums/showthread.php?t=48306&highlight=salinity</a>
Edit: I can't find the other thread where Seachem responded, its a pretty long thread and they explain it in detail. After I started using it I made it my mission to follow the advice of seachem and see if I could pull it off. Basically what you need is patience. My water changes are 20 gallons. So I have the 20 gallons of RODI water, I add about 4 cups right off the bat, let that mix for a few mins then add about 2 more full cups. Then I slow it down and add half a cup at a time about every 10 mins. You have to refrain from dumping it in all at once. Another tip is when you add your cups and your half cups pour the salt in slowely dont dump it in. Sprinkle it. Alot of people whine that they don't have the time and just deal with the film. I have the few extra mins and do it right and I have ZERO film.
Hope this helps.
In my link was the first times I was figuring out how to do it and took it really slow. Way too slow. I do it how I described in this thread now to cut down on time.
Search for that other thread that seachem was involved in and it will explain in detail what is happening and what the film is. The film is basically calcium snow. You get is because you add the salt to quickly to the water and it can't absorb it properlly and snows it out.