[Maverick00]

So im trying to dial in my parameters for mixing NSW in my new 20 gallon rubbermaid. I added 15 US Gal of RODI water and 2350g of IO Salt which brought me to 1.026. Ok easy enough, now onto water chemistry.

My first test was for magnesium which came out to 1267ppm. (Im using a Salifert test kit which is still good for the record) Not bad but i was shooting for around 1300. Im using brightwell aquatics products at the moment and reading the back of the powered magnesium supplement..
"Reference: Each g of Magnesion-P will increase the [Mg2+] in 1 US-gallon (3.785 L) of water by 114.4 ppm.]"
Using this reference I figured each gram of powder would boost the mag in my 15 gallons of saltwater by 7.63ppm. To keep things simple I added 5 grams to the new saltwater hoping for a reading of around 1305ppm. After dissolving the powder and retaking the reading, im left with the same amount of mag as before, around 1267ppm.

Am I missing something here? Anyone else using powered brightwell aquatic products and have any similar issues? I remember a few months ago when I tried doing the same thing only with 10 gallons of saltwater, I had to add WAY more than what the instructions stated to get anywhere near what i wanted. Im going to go ahead and test for calcium now.