My LFS says that by using RO water you actually remove a lot of what salt vendors expect to be present in the base supply, thereby causing trace elements to be omitted when you do a water change.

I've just bought a 5-stage RO for my setup and even though I'll use a supposedly premium salt, should I be adding anything else?

Can someone recommend anything? The tank is mainly coral and invert with a light fish load.

Scott.

My LFS says that by using RO water you actually remove a lot of what salt vendors expect to be present in the base supply, thereby causing trace elements to be omitted when you do a water change.
i do not agree with this. in fact, if you check the bag/bucket of salt you have, (mine is Instant Ocean) you will see that they recommend the use of purified water or at least dechlorinated. while its tru that tap water does contain a lot of good trace elements, it also contains just as many bad elements and chemicals. in fat if you go to just about any forum or check articles written by industry experts they pretty much all recommend the use of RO/DI water or Distilled water.

I've just bought a 5-stage RO for my setup and even though I'll use a supposedly premium salt, should I be adding anything else?
Can someone recommend anything? The tank is mainly coral and invert with a light fish load.
Scott.
there is no simple answer to this. you should add what you need. for example, while your tank is still young, simple water changes will be enough. As your needs increase, you may need to add things like iodine, calcium, alkalinity buffer, PH buffer, or magnesium. But that said, the best thing to do is to monitor your water with a good test kit(s) and add whats needed.
you can also reduce the amount of things you need to add by doing more frequent water changes. instead of doing 20% a month do 5% a week. this will help in many ways, it will restock major and minor trace elements, and will help reduce pollutants in the water.

i hope i answered all your questions, if not, let me know