Adding magnesium powder

Amanda 234 · Feb 12, 2025

Hi can anyone help I’ve mixed 20g of magnesium powder to 250ml of water can I add it all to my top of tank or does it have to go in bit by bit also is it the front top off tank that goes back into the tank or the back tank that you fill thank you

Randy Holmes-Farley · Feb 12, 2025

What size tank?

How do you know you need it?

Amanda 234 · Feb 12, 2025

Done a magnesium test and it come out has 0.2 which I take has 1200 and my tank size is 326 litres

get-salty · Feb 12, 2025

You can add whatever you want into a tank and as much as you want, if and only if, there is no living creatures in the tank. If you have corals, highly recommend adding any additives 'bit by bit" on a daily basis. Also, you dont need mag if you're not keeping corals.

I'm also a bit confused on that mag test of yours.

good luck and happy reefing

Randy Holmes-Farley · Feb 12, 2025

Amanda 234 said:
Done a magnesium test and it come out has 0.2 which I take has 1200 and my tank size is 326 litres

Let’s be sure you actually have that level and that dosing is the best way to achieve normal levels. Low salinity and inaccurate mag testing are both very common.

How are you measuring salinity, how did you calibrate that device, and what do you think it is?

How are you measuring magnesium?

Amanda 234 · Feb 12, 2025

Salinity meter calibrated it from instructions meter is saying it between 1025/1026 and magnesium is a salifert magnesium test

Randy Holmes-Farley · Feb 12, 2025

Amanda 234 said:
Salinity meter calibrated it from instructions meter is saying it between 1025/1026 and magnesium is a salifert magnesium test

What salinity meter? That can mean many different brands and even types of devices.

What salt mix are you using? Have you tried the kit on it?

Amanda 234 · Feb 12, 2025

Salt we are using h2ocean classic formula salinity meter is picture sent through and we have a cop test kit to do

Amanda 234 · Feb 12, 2025

Icp test that was meant to be sorry

Randy Holmes-Farley · Feb 12, 2025

Amanda 234 said:
Salt we are using h2ocean classic formula salinity meter is picture sent through and we have a cop test kit to do

I’d suggest making a diy calibration fluid if you have a scale. If not, try a different brand fluid, such as American marine/pinpoint.

Also try that mag kit on new salt water.

Note that water with mag = 1300 at 35 ppt (sg = 1.0264) will only have 1231 ppm at sg = 1.026.