Magnesium too high, all the time.

reeferdon · May 29, 2018

The River said:
I am really struggling in the same boat... AF reef salt, dosing components 123 minus 3 because of mag issue... On a doser. Red sea test kit reads 1620 to 1640 ish. Did a 20 percent water change today with Instant Ocean Salt (not reef) and still have mag at 1600... Really looking for some advice. Cant get my magnesium down

Truthfully I don't try to lower my mag anymore. I focus on Alk and Calc because they're what my tank uses the most. Mag is still over 1500. Having no issues with live stock.
Considering trying the HW salt instead of AF reef salt on my next salt order.

Randy Holmes-Farley · May 29, 2018

The River said:
I am really struggling in the same boat... AF reef salt, dosing components 123 minus 3 because of mag issue... On a doser. Red sea test kit reads 1620 to 1640 ish. Did a 20 percent water change today with Instant Ocean Salt (not reef) and still have mag at 1600... Really looking for some advice. Cant get my magnesium down

The Red Sea magnesium kit causes a lot of confusion for reefers. Did you try the kit on the IO?

FWIW, a 20% change won't do a huge amount. If you are at 1600 and do a 20% change with 1300 ppm water, the magnesium only drops to 1540 ppm.

The River · May 29, 2018

Randy Holmes-Farley said:
The Red Sea magnesium kit causes a lot of confusion for reefers. Did you try the kit on the IO?

FWIW, a 20% change won't do a huge amount. If you are at 1600 and do a 20% change with 1300 ppm water, the magnesium only drops to 1540 ppm.

I did not test the Instant Ocean but saved about a gallon of it and put it aside... I assumed the Mag level was low but totally will test that level when I get home. I realized that to make sense with any math I need that Mag level as well...

Are there any easy ways to validate the mag test kit reading? Like a simple stable mag solution I can test against, etc?

The River · May 29, 2018

To follow up... The water I made to dilute my Mag was tested at 1520... So that makes sense as I assumed it was in the 1300-1350 range.

The River · May 29, 2018

I will be the first to admit, I read several threads on this issue and at least one person always mentioned to used a CALIBRATED refractometer. Well mine was calibrated about 6 weeks ago.... So I can ignore that advice, right?
After chasing my tail for weeks and switching salt mix, I realized the IO salt was reading Mag way too high and so was the AF salt mix.
I stopped calibrated my refractometer and realized my tank and newly made salt were around 37 ppt. So chalk that up as lesaon learned. I am slowly letting my ATO bring it down by removing some tank water every hour until its good again around 35ppm. Just for closure I will post my new Mag results tomorrow night after it stabilizes.
Disclosure: AF salt still has high Mag at 35ppt but more in the 1500 area

Randy Holmes-Farley · May 30, 2018

Thanks for the update.

tigertym57 · May 30, 2018

I have the same problem using aquaforest reef salt. I have tested my magnesium multiple times and it's always at or above 1600. I kept thinking it was the test kit and bought several different brands, but to my surprise, I sent in two separate ATI lab tests and both came back at 1385...go figure. Both tests were done 2 months apart. On a separate head scratcher both lab tests showed my salinity being a lot lower than my apex and calibrated refractometer (31.64). Anyways, I'm assuming most aquaforest salts are all high in magnesium.

The River · May 30, 2018

tigertym57 said:
I have the same problem using aquaforest reef salt. I have tested my magnesium multiple times and it's always at or above 1600. I kept thinking it was the test kit and bought several different brands, but to my surprise, I sent in two separate ATI lab tests and both came back at 1385...go figure. Both tests were done 2 months apart. On a separate head scratcher both lab tests showed my salinity being a lot lower than my apex and calibrated refractometer (31.64). Anyways, I'm assuming most aquaforest salts are all high in magnesium.

Well that is good to hear... I am going to keep an eye on it but my tank and corals look happy so like mentioned I will stay focus on Salinity - ALK - Ca
I do plan to stay using Instant Ocean Reef Salt now I made the switch and purchased a huge bucket so hopefully I won't be chasing the Mag level around from the Aquaforest salt anymore.

reeferdon · May 30, 2018

The River said:
Well that is good to hear... I am going to keep an eye on it but my tank and corals look happy so like mentioned I will stay focus on Salinity - ALK - Ca
I do plan to stay using Instant Ocean Reef Salt now I made the switch and purchased a huge bucket so hopefully I won't be chasing the Mag level around from the Aquaforest salt anymore.

Mag is still high with the AF reef salt and this is my second bucket of reef salt. Even though Aqua Forest sent me the ICP test for the salt it don't add up.
I still like Aqua Forest but gonna try other brand of salt.

reeferfoxx · May 30, 2018

Red Sea Blue bucket has low 1200's on magnesium.

trustmeimalawyer · Feb 6, 2019

I know this is an older thread but I am having the same exact issue with a brand new Red Sea test kit. After using up the entire 1ml of titration the color still did not change to blue. I filled up half the syringe again and still no blue. Again, brand new test kit and refractomer is calibrated (digital Milwaukee). Using Fritz salt.