Excessive Magnesium levels suddenly, after being fairly stable for months.

[fluked]

Please help identify why my mag levels are rising (from my testing) I suspect faulty salifert kit, but would welcome other ideas.

The issue I'm seeing is increasing Mag levels, in the last few weeks my mag has been increasing, until mid July was hovering between 1300-1450 ppm (I'm using salifert test, and not particularly trying for perfection, unless i get a weird result then ill retest much more strictly). so I'm generally fine in that range
.
I recently completed a triton icp test, (sent the sample 18th July) and had magnesium level of 1377 ppm according to that, my testing at the same time was 1470 (18th july), which definitely higher than the triton result, wasn't too surprising, but i stopped dosing mag after that result.

However after receiving the icp result, i've done 3 more tests, 1 was 1500, (july 25th) and 2 more tests August 1st (over 1500 and 1600), definitely seems like there's in issue with my test kit however its weird, because it was getting normal results for a while, until it suddenly went way out of range. But if anyone has an idea of other magnesium sources that may be the cause that would be great.

What I am now dosing: 2 part (Reef revolution calcium ~2/3ml per day + Aquaforest KH Buffer ~12 ml per day), I was dosing reef revolution magnesium at ~2/3 ml per day but have stopped, I was also dosing reef secrets iodine, but have also stopped that post icp test

Also, my water change schedule is just under a 10% water change weekly, using aquaforest reef salt

Cheers

 

[Forty-Two]

I’m not an expert expert but I would to test the RODI water and see what’s there and then test after adding the salt. At the very least you can rule out those sources and then look at other options.

 

[fluked]

Good point,
I've tested my salt with rodi in the past and got an in range value, but haven't done that recently. I'll test again and update this.

 

[maroun.c]

Small differences between icp and test kits are fine id say up to 30-50 difference is no big deal as mag ok range is quite wide.
For the increase i would doubt its a real reading and suspect testing error or test kit issue as it takes a lot of dosing to raise mag especially if tank size is big.
Test fresh mixed salt. I doubt Aquaforest has high mag in their salt but it could have been some settling or a bad batch. Yet never saw high mag in their salt.
Try to cross check with another kit and see if changes across a period of time are linear between the two kits.