Tropic Marin Pro Low Magnesium

Randy Holmes-Farley · Sep 23, 2023

FWIW, NSW with 1300 ppm magnesium at 35 ppt sg = 1.0264) will have 1232 ppm at sg = 1.025.

Jason K · Oct 10, 2023

Pod_01 said:
Unlikely, Mg seems very difficult to be measured or inconsistent.
Source of potential error are salinity, test kit and unfortunately the user.
I personally have hard time measuring Mg and I been doing it for 6 years.

Out of curiosity how do you measure salinity?

Also recommend salinity is 1.0262 so yours if correct should have less Mg.

Good luck,

Two different tests. Calibrated against a standard. Did the test 3 times. Consistent results.

Salinity measured with a refractometer. I test the salinity of every batch of water i make, and it's a consistent 1.025

Jason K · Oct 10, 2023

areefer01 said:
Well my first suggestion is to not chase numbers. You will just end up in crazy town.

You call it chasing, I call it having consistently low Mg in my tank and wanting to bump it up the recommended range.

Randy Holmes-Farley · Oct 10, 2023

Jason K said:
You call it chasing, I call it having consistently low Mg in my tank and wanting to bump it up the recommended range.

Chasing aside, even if the magnesium is low (magnesium testing is likely one of the most inaccurate sets of tests we use), it is at least partly low die to the salinity being low as I mentioned, and raising it immediately solves half of your problem.

Then if you want to raiser it further, that is easy to do.

Garf · Oct 10, 2023

Jason K said:
Two different tests. Calibrated against a standard. Did the test 3 times. Consistent results.

Salinity measured with a refractometer. I test the salinity of every batch of water i make, and it's a consistent 1.025

How are you calibrating the Refractometer?

Jason K · Oct 10, 2023

Randy Holmes-Farley said:
Chasing aside, even if the magnesium is low (magnesium testing is likely one of the most inaccurate sets of tests we use), it is at least partly low die to the salinity being low as I mentioned, and raising it immediately solves half of your problem.

Then if you want to raiser it further, that is easy to do.

yep, agreed. I have started to dose Mg into my salt mix, so that I get test readings of 1200 at 1.025. So even if my test results are faulty/low, I think I'd be in a good range.

Jason K · Oct 10, 2023

Garf said:
How are you calibrating the Refractometer?

refracto juice....every time i test

Garf · Oct 10, 2023

Jason K said:
refracto juice....every time i test

Don’t suppose your magnesium standard has a salinity reading on it, just to double check? I use Randys DIY standard.

Jason K · Oct 31, 2023

Garf said:
Don’t suppose your magnesium standard has a salinity reading on it, just to double check? I use Randys DIY standard.

I don't understand this comment. I'm already calibrating my refractometer against a standard.

Anyway the magnesium standard is Fauna Marin Multi reference, and it does have a known salinity of 35ppt /1.026sg

Garf · Oct 31, 2023

Jason K said:
I don't understand this comment. I'm already calibrating my refractometer against a standard.

Anyway the magnesium standard is Fauna Marin Multi reference, and it does have a known salinity of 35ppt /1.026sg

I think you’ve been using the BRS refracto juice to calibrate, I was suggesting using the magnesium standard to calibrate the refractometer if it had a known salinity (which it appears it does), just to double check, if indeed it’s applicable to refractometers (dunno if you need to consult Fauna Marin for that). Did you sort your problem? Where have you been for 3 weeks? Lol.

Edit - Appears it is good for refractometers