Do I need to switch salt?

[DiverDude]

Originally Posted by JenniferL

I recently upgraded to a 90gal and got my new RO/DI unit. Since switching to RO water my calcium and levels have dropped from 420 to 320-360ppm and alkalinity from 8 to 6. I happened to be in my LFS and they advised me that I should have switched my salt from IO to the Red Sea salt. I just bought a new pail, so he sent me with Seachem advanced Calcium and Reef builder powders to use until I use up the IO. I would like to try some SPS corals in the future and wanted to get this corrected now before I have a bunch of corals. Just wondering what you guys suggest.

Very interesting. I've used RO/DI water since I setup a few months ago and I only recently added a few softies and as of 2 days ago now have a single SPS frag (so there's nothing sucking calcium out of my system) and my Ca levels are only marginally better than yours at 375 -and that's the day after a 5 Gal water change (on a 29 Gal tank). Alkalinity is way down at 4.

From what I understand, the advantage to RO/DI is that you start from a know basepoint (i.e. pure H2O). Your tap water may actually have beneficial levels of some salts but water in, say, Ontario may not. So if we all want to share information it needs to have a common reference point on which to start talking about salts, additives, etc. Otherwise, we all go off on our own and see what works.

I'm far from an expert on this but my thought is that no salt is going to give you consistently perfect seawater for every kind of setup. Each tank is different and has different requirements. Our job as aquariasts is to monitor those needs and adjust accordingly to provide the best environment we can and I think that means we all have to use at least SOME additives to get the job done.