You shouldn't need to add sodium bicarbonate to IO, but you will need to add magnesium and calcium! IO usually tests at 11 dKH for me, only 1150 ppm magnesium, and only 360-380 ppm calcium. My only real complaint about IO is the alkalinity is too high for my liking. I keep alkalinity in my reef 7-8 dKH, so if I do a big water change I get a big alkalinity swing. That was one of my main reasons for switching to H2Ocean. Even though the numbers of the H2Ocean are nicer I didn't notice any benefit in my reef after using it for 14 months. My reef is back on IO. I have tried most of the salts on the market, and I have never found my inhabitants to care which salt I used. That's the ultimate factor I think.

I mix IO and RC. As Myka mention IO calcium is around 360-380. RC calcium is about 450. mixed at 50/50 calcium comes out at 410 but Alk is still a little high for my liking at 11 dKH.

Warning: I have heard that mixing salts can cause "stuff" to precipatate out but so far IO and RC mix just fine.

Oceanic salt is cheap, has a lower dKH but is also high in calcium. I may try mixing Oceanic with IO but the closest I can find Oceanic salt is in Bellingham.

*I'm gonna try bringing 100lbs of white powdery stuff across the border and tell the gaurds it is for my fish tank

This is the one issue I have with RC... the Calcium spike because as you said it tests at 450 (tests even higher for me). My 400 tested at Ca 480 and I've yet to begin dosing Ca due to this as levels are dropping much slower in 4x the volume.

solution, change less of the water but more often.. I now change 15% every 2 weeks instead of changing 30% once a month. just 15% does not change the alkalinity too much and I stop dosing for a day since I don't need to for a day or 2, then I resume my dosing pumps.

The more I got in alkalinity raise was 8.5 and I keep mine at 7.5

So is there much of a difference between IO salt, and IO Reef Crystals salt? (Reef Crystals being the more expensive of the two options).

Yeah this is only a minor complaint of mine because normally I only do 10-15% weekly and factor the small increase into my dosing schedule.

Every now and then I like to do a larger change though and this is when It's a bit annoying.

Yes I have the same thing hapening when I do a large water change and I have to cut off my dosing pump for a few days until things gets lower. But if your alkalinity is 7 and you change 50% or the water with alkalinity 11, that should bring it to around 9, so if you change 25% it should only be around 1 point so not that big of a change.

Still, one point is sometime enough to disturb sensitive coral but I had swing going from 6 to 8 in one day before I was using dosing pump and I never lost a coral from that.

I too wish RC would be more around 8 in alkalinity since I am dosing.

It's the high Calcium I'm referring to actually. Mine usually tests 450 - 480. Sometimes as high as 500.

hahah!!!

I change 20% once a week and I have not been dosing alk since starting I also haven't done a test in a while so on Sunday-mon when I do my w/c I'll test tank currently test new water and test the tank after the change and I'll post my findings All I know is my tank has visibly improved since switching so it obviously likes the salt more then standard IO