Mag-ca-alk-sg Balance

[chrisreef]

Hi folks,


I'm aware how the level of magnesium has an effect on the calcium/alk balance as well as does the SG.

But does anybody have any info or links which show as to what degree the level of Magnesium or SG effects the balance?

A graph or mathematical formula would be an added bonus!

Chris.

[danny]

The level of magnesium is dependent on salinity, so if you aim for 1350ppm at an sg of 1.025 or salinity of 35ppt you will be about right. Obviously if you have 20% less salt (28ppt) your magnesium will drop proportionally.

[Glenn@home]

I think its fairly simple to work out because were are simply talking about ratios of substances

nsw has a salinity around 35ppt and Mg will be around 1300ppt.

So i think its a simple matter of reducing the mg concentration by a similar proportion to get a value for proprortions of Mg in your water.

E.G. If the salinity is at 34 ppt then the mg to be in correct proportion would be (1300/35) x 34 = 1263 ppt.

FWIW I would aim for nsw levels of 35ppt then theres no confusion ogver whgat your parameters should read and the critters arelikley to be happiest (IIRC typically average salinty ranges from 35 - 37 ppt)

HTH

Glenn

[chrisreef]

Thanks guys.

One further question then, what would be the effect of too much magnesium? (Just a what-if question)

[elliot]

No real effect upto 1500... never taken it higher.

elliot

[Shultz]

Most people who want a high cal go for a high mag to keep it there, iirc mag should be atleast 3 times the cal

eg 450 cal = 1350 mag

Cheers Shelton.

[danny]

I think the idea is that the magnesium forms temporary bonds with bicarbonate molecules allowing you to hold more calcium in solution without precipitation. Well that is the theory I heard