Magnesium rise without dosing?

[Yamaha1634]

Have a new tank set up for 6 weeks or so. Have completed two water tests 5 days apart and seen a large magnesium rise. Timeline below. Tank is 13 gal.

Nitrate is an API kit, others are red sea foundation pro kit

Tank stocked with 2 clowns and a duncan coral.

15th Feb water test
Salinity 1.026
Nitrate 10
Calcium 430
Magnesium 1320
Alkalinity 7.8

18th Feb added hammer coral, candy cane and 5x brown leg hermit crabs, also a 10% water change at the same time as was removing tank water for acclimating and dipping etc

20th Feb water test
Salinity 1.026
Nitrate 10
Calcium 430
Magnesium 1560
Alkalinity 7.8


Any reason why my magnesium would rocket like that? Also is it dangerous and how do i rectify it if I need to??

 

[Garf]

Have a new tank set up for 6 weeks or so. Have completed two water tests 5 days apart and seen a large magnesium rise. Timeline below. Tank is 13 gal.

Nitrate is an API kit, others are red sea foundation pro kit

Tank stocked with 2 clowns and a duncan coral.

15th Feb water test
Salinity 1.026
Nitrate 10
Calcium 430
Magnesium 1320
Alkalinity 7.8

18th Feb added hammer coral, candy cane and 5x brown leg hermit crabs, also a 10% water change at the same time as was removing tank water for acclimating and dipping etc

20th Feb water test
Salinity 1.026
Nitrate 10
Calcium 430
Magnesium 1560
Alkalinity 7.8


Any reason why my magnesium would rocket like that? Also is it dangerous and how do i rectify it if I need to??

I imagine it’s a testing error of some sort. I’d be checking the freshly made water for magnesium and salinity. How are you checking salinity and how is it calibrated?

 

[Yamaha1634]

I imagine it’s a testing error of some sort. I’d be checking the freshly made water for magnesium and salinity. How are you checking salinity and how is it calibrated?

Ran the magnesium test twice to make sure and got the same result both times, first result was 1560, second result was 1600!

Salinity is taken with a refractometer, calibrated with fluid around 4 weeks ago. Salinity readings have been stable. There is a chance it's gone out of calibration but surely i would see fluctuations in the salinity? It's been pretty stable for weeks.....

Is that level of magnesium a problem for livestock?

 

[Garf]

Ran the magnesium test twice to make sure and got the same result both times, first result was 1560, second result was 1600!

Salinity is taken with a refractometer, calibrated with fluid around 4 weeks ago. Salinity readings have been stable. There is a chance it's gone out of calibration but surely i would see fluctuations in the salinity? It's been pretty stable for weeks.....

Is that level of magnesium a problem for livestock?

Apparently snails don’t like it much. However, it ain’t just gone up on its own.

 

[Yamaha1634]

Apparently snails don’t like it much. However, it ain’t just gone up on its own.

How about frozen foods? I fed frozen brine shrimp yesterday but only half a cube....

 

[Garf]

How about frozen foods? I fed frozen brine shrimp yesterday but only half a cube....

Nah, you have to add loads of magnesium to make the numbers go up. Check some fresh made saltwater.

 

[Yamaha1634]

Nah, you have to add loads of magnesium to make the numbers go up. Check some fresh made saltwater.

So fresh salt water tested to 1,840!!!

 

[Yamaha1634]

Actually I'll correct that, it's off the scale so I've had to calculate it myself, I'd say it's closer to 1900 magnesium.

 

[Garf]

So fresh salt water tested to 1,840!!!

Calibrate refractometer, then test fresh salt water for salinity.

 

[Yamaha1634]

Salinity 1.026 on fresh salt water.

I'm buying it from my LFS as the tank is so small it made more sense to buy it premixed rather than make my own rodi and mix salt....

I called the shop. He said he's using Tropic Marin salt same as he always has and blames the high magnesium to a "hot spot" in the salt mix... That make any sense to you??

 

[Garf]

Salinity 1.026 on fresh salt water.

I'm buying it from my LFS as the tank is so small it made more sense to buy it premixed rather than make my own rodi and mix salt....

I called the shop. He said he's using Tropic Marin salt same as he always has and blames the high magnesium to a "hot spot" in the salt mix... That make any sense to you??

Sometimes there can be dodgy batches, or batches that are not fully mixed. There’s been an undefined manufacturing problem with tropic Marin pro reef salt from Turkey, recently. Sounds like he should swap your water with some proper stuff.

 

[Yamaha1634]

Sometimes there can be dodgy batches, or batches that are not fully mixed. There’s been an undefined manufacturing problem with tropic Marin pro reef salt from Turkey, recently. Sounds like he should swap your water with some proper stuff.

Agreed. Will discard all I have left and buy new from elsewhere. Not sure I want to get into mixing my own so will move to a different LFS for water.

I've been getting my fish and corals from a place an hour away from me as he's the best selection and the cleanest looking tanks I've seen, this is where I've been getting water. There is another place much closer that has clean tanks but very limited selection, he does mainly freshwater but I'll try his saltwater out and go from there. Would be nice to get water from somewhere close even if i have to travel for livestock!

 

[Randy Holmes-Farley]

It's almost certainly test error, not a bad batch. he rise by 240 ppm in 5 days proves, it. That cannot happen without adding massive amounts of a supplement. In a 100 gallon tank that would take nearly 2 pounds of dry additive.

Magnesium kits are often inaccurate. the forum is filled with such threads.

IMO, most folks are better of never measuring it.