Raising Mg

[StirCrazy]

Originally Posted by Johnny Reefer

Just lookin' for opinions on this.
I'm using SeaChem Advantage Mg to raise my Mg from 975 to 1,290.
The jar says that 5 grams will raise 21 gallons by 5ppm.
My system is 205 gal net.
205/21=9.76. Right?
9.76 x 5g= 48.8grams. Right?
1,290ppm - 975 ppm = 315ppm. Right?
315ppm/5ppm = 63. Right?
63 x 48.8grams = 3,075 grams. Right?
This seems like a whole whack o' Mg to me.
I have to dose over 3 Kg's of Mg to get up to 1,290ppm???
Does this sound right?
Anyone else ever have to use so much Mg, initially?
(Seems like I'm gettin' a calculation wrong here?).

Thanx much,

nope sounds close. what you should do is take some warm RO water and dissolve say 1 cup of the reef advantage in it (this is the same stuff I use) then add that to your sump. the next morning measure your Mg and see how much it increased. Now you really got to look at it and ask do you really have 208 gal of water in your tank, how much does the rock displace ect...
I do this test with 1/2 a cup but you should have at least twice the volume of water as me so it will be better with 1 cup. and I will tell you it takes a lot to bring it back up but then you will hardly use any for a long time.

I should also note I raise my Mg by 100 ppm per day approximately and have never had a problem with anything at this rate.

Steve