I just measured a new batch of IO salt with a salifert kit and found the Ca to be at 310 ppm. Finding this a bit low, I did some research and found the article by Bingman in which he compares salt brands. According to that study, the Ca in IO salt should be 360 ppm. Even this number surprised me as I figured newly mixed salt should be about 400 ppm, or close to natural sea water. My question is this: have other hobbyists reported levels of Ca in IO salt to be this low? And why is this brand so popular if other brands (Kent, Coralife, Seachem) have Ca levels equal to or higher than NSW. I will probably just raise the Ca with CaCl but I am considering switching brands so this isn't neccesary in the future. Thanks for any input.
Instant Ocean Ca levels
- Thread starter rajah
- Start date
IO usually comes in in the mid 300's for calcium. Folks (like myself) figure that we are supplementing calcium anyway. A little more here or there is not a big deal.
What salinity did you make the water up to?
What salinity did you make the water up to?
I mixed it to 1.025. I just thought having to add around 70 ml of liquid calcium (Kent, according to the calculator) to each new batch of 15 gallons would get a bit expensive. But, I see your logic. I will have to look into cheaper sources of Ca, like the de-icer you have written about. Thanks for the reply.
Yes,I use Dowflake to boost mine. Also, with a bit higher salinity, matching NSW with a sg of 1.026-1.027, the calcium will come up some. 
DrBDC
New member
I haven't tested in about a month and a half but I was finding that in a 32 gallon brute mixing container, 1 cup of Randy's formula 2 Ca and 2 cups of the mag formula got me just about right on ca and mag. I did test my mag on the system a week ago and the mag was slowly raising and was up to 1400 so I'm overshooting a little on the mag but the ca was right on.
FWIW, I posted on the wall over my 88 gallon new salt water holding container how much Dowflake and DSW magnesium chloride to add to typical IO to reach nice levels. I don't bother to measure the new salt water, only the aquarium itself.
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