Calcium in salt?

[mswt5]

I have a question about salt......I know the salt comes with Calcium in it but how much.....400 is normal level of calcium in the sea but were always striving for more.....what is the calcium level of a new batch of salt water???....and if its 400 why dont they sell salt for reefers who want it higher??

[Anemone]

Dr. Ron has discussed the contents of saltwater in a series of articles in Reefkeeping magazine. In one article he listed Instant Ocean mix as having a calcium content of 400 ppm (this article).

Kevin

[Randy V]

The easy way to find out is to test a batch of freshly mixed saltwater prior to your next water change. I would bet there is a fair variation between different brands. The one I use tests out lower than I like for both calcium and alkalinity using my home test kits so I add a little calcium and buffer to the waterbefore I use it in a change.

[ReefRaf]

Originally posted by mswt5
I have a question about salt......I know the salt comes with Calcium in it but how much.....400 is normal level of calcium in the sea but were always striving for more.....what is the calcium level of a new batch of salt water???....and if its 400 why dont they sell salt for reefers who want it higher??

The problem with that idea is that even if they made salt with 500ppm, Ca depletion due to uptake by corals would require you to add more in a couple of days anyway. That's why we continue to add calcium....it gets used up quickly.

[Randy V]

Still, you would like to use replacement water for changes that approximates the parameters of the existing water. That way you don't have to remember to adjust your dosing amounts just after doing a water change because your low ca salt mix just diluted your system.

I see from the article that Anemone linked that salt mixes varied between 210 and 560 ppm. That's a huge variation. If it were me, I would test my mix.

[Anemone]

Originally posted by Randy V
I see from the article that Anemone linked that salt mixes varied between 210 and 560 ppm. That's a huge variation. If it were me, I would test my mix.

Those numbers were from samples of water from people's tanks, not fresh salt mixes.

Kevin

[Randy V]

Thank you anemone, I missed that important distinction.