Why is my Magnesium over1600?

[LardLad]

I use RSCP in a 13.5 EVO. It is la lightly stocked mixed reef with no dosing. I mix at 38gm/L. I change 40% once per 2 weeks.
My test kit only goes to 1600. So I went to my LFS who I trust. His test goes to 1800. He said my mag was off the chart.

Im not sure whats happening

 

[Terry Mattson]

So what specific gravity is 38mg/l? I thought 35mg/l is 1.026. ???

 

[LardLad]

1.026

 

[LardLad]

All other params are perfect and stable

 

[LardLad]

 

[fcmatt]

Did you test your fresh saltwater after it was fully mixed for several hours? I bet the mg is off the charts as well. Most obvious problem in my mind. Mg does not come out of no where.

 

[fcmatt]

1.026

38 is not 1.026. It is 1.026 at like a temp of 84 degrees and up. I have a feeling u r way high salinity wise and that is the next obvious issue to check

Google for a salinty chart to see what we mean. Temp makes a huge difference. You might very well be at 1.027 or 1.028 even depending on how u check salinity which u need to tell us

 

[Terry Mattson]

1.026

Ok. That rules out one cause. I looked up rscp specs as addvertised. Only thought is the salt in the container needs to be mixed. I have seen salts settle out but I do not use rscp. Sorry I cannot help more.

 

[fcmatt]

Ok. That rules out one cause. I looked up rscp specs as addvertised. Only thought is the salt in the container needs to be mixed. I have seen salts settle out but I do not use rscp. Sorry I cannot help more.

I think u nailed it with your first post.

 

[Terry Mattson]

I think u nailed it with your first post.

Ya, just wasn't sure the conversion. Plus did not ask enough questions. I use fritz salt and mix at 78 degrees to achieve 1.026. Use Milwaukee tester .... hopefully your input will help the guy.

 

[JP Reef]

salinity isn't measured in mg/L. That is the mixing ratio according to the chart it looks like. Salinity is measured in parts per thousand (ppt), relative specific gravity (sg), and conductivity (mS/cm). I would also like to point out that the actual salinity doesn't really change with temp, but appears that way due to how we measure it which is why some refractometers have a auto temp correction.

 

[JP Reef]

I would test the new salt to see what magnesium level is. Since you don't dose that would likely be the only possible source.

 

[Terry Mattson]

One other thing to check is to make sure the instrument used to check specific gravity is calibrated. My Milwaukee checker was reading a little low 1.026 when it was 1.028. Checked with a back up. Recalibrated with solution and it read 1.026. I have a ph probe, good one. It was reading 8.2 to 8.3. Then decided to check using a chemical method. It read 7.8 to 7.9. Yup, recalibrated the probe. Periodic calibration check is important. Early lesson learned in this hobby ....

 

[fcmatt]

Ugh. I need to check my reading comprehension. I read right past the whole gm/l and in my mind thought ppt was meant.

Thank u about how we measure it explanation. For example when I use my refractometer I always pause for a moment or three to let the saltwater adjust to the temp of the device since I tend to mix in cooler water... and then I know it is closer to room temp then the colder I mixed in.

I calibrate using 2 solutions from diff manufacturers at room temp.

So now we need to know how the person measures salinity, calibrates, and what is mg in fresh mixed saltwater.

 

[Particle]

OP - did you ever figure this out? I'm in the same boat, but haven't tested mg in freshly mixed water yet. I do use RSCP as well. Next step, testing some newly mixed water...

 

[Terry Mattson]

OP - did you ever figure this out? I'm in the same boat, but haven't tested mg in freshly mixed water yet. I do use RSCP as well. Next step, testing some newly mixed water...

Make sure you mix the salt at the recommended temperature and specific gravity. Additionally, check the instrument is calibrated. I have two methods to check salinity to keep things honest.

 

[LardLad]

Yep I use an auto temp corrected refractometer with dual liquid controls. I check it several times through the mixing process I mix in a clean container at 78 degrees with a pump set to 360 gph. I use digital scales to measure out the salt and correct to the gram to exactly 1.026 salinity at 78F.
I appreciate everyone who said that 35 parts per thousand produces 1.026 salinity however with the additives that are in salt mixes it ends up being 38.2 grams per liter for this salt mix as there is more than just salt in these Marine salt mixes. So each individual product will mix up differently regarding grams per liter.

Finally for those who suggested that I mix up fresh saltwater and then test it I think you. This RSCP mix mixed with RO water at 78F at precisely 1.026 salinity produces a magnesium reading of over 1600 mg per multiple tests.

 

[Terry Mattson]

Yep I use an auto temp corrected refractometer with dual liquid controls. I check it several times through the mixing process I mix in a clean container at 78 degrees with a pump set to 360 gph. I use digital scales to measure out the salt and correct to the gram to exactly 1.026 salinity at 78F.
I appreciate everyone who said that 35 parts per thousand produces 1.026 salinity however with the additives that are in salt mixes it ends up being 38.2 grams per liter for this salt mix as there is more than just salt in these Marine salt mixes. So each individual product will mix up differently regarding grams per liter.

Finally for those who suggested that I mix up fresh saltwater and then test it I think you. This RSCP mix mixed with RO water at 78F at precisely 1.026 salinity produces a magnesium reading of over 1600 mg per multiple tests.

Wow. Idk. RSCP has elevated parameters but that is high. You may need to consider changing salts.

 

[Particle]

Yep I use an auto temp corrected refractometer with dual liquid controls. I check it several times through the mixing process I mix in a clean container at 78 degrees with a pump set to 360 gph. I use digital scales to measure out the salt and correct to the gram to exactly 1.026 salinity at 78F.
I appreciate everyone who said that 35 parts per thousand produces 1.026 salinity however with the additives that are in salt mixes it ends up being 38.2 grams per liter for this salt mix as there is more than just salt in these Marine salt mixes. So each individual product will mix up differently regarding grams per liter.

Finally for those who suggested that I mix up fresh saltwater and then test it I think you. This RSCP mix mixed with RO water at 78F at precisely 1.026 salinity produces a magnesium reading of over 1600 mg per multiple tests.

Glad I am not the only one experiencing this. I haven't tested it fresh, and will next water change, but I have an Apex Fusion with probe, use a refractometer, and do not dose mg. Similar to LardLad I measure everything out with a scale, bring the RODI water up to temp first, and check that everything matches before adding. I'd be shocked if I were that far off - and I've had this tank running for over 2 yrs (RS Max Nano).

 

[Particle]

Next question is, is 1600mg necessarily bad?