Magnesium dropping and calcium

alexanderthefishlover · Dec 4, 2024

Hello,

So basically I found my magnesium had dropped to 1200 ppm. I dosed it back to 1340ppm over a course of 3 days.

I left it for a day and just tested and it dropped by 20 ppm in a day? Is this normal? This not a large aquarium and I have soft corals and a few LPS that are not large.

My calcium was at 340 ppm and I’ve got it to 440ppm and that also dropped by 20 ppm in a single day.

I do not have a lot of corraline algae only some on shells and on live rock (want to grow more)m desperately think it’s beautiful!)

I can’t get my hands on a strontium test however I began dosing a small amount the other day. I also began dosing iodide. Really trying to get more corraline algae growing.

Are these drops in magnesium and calcium normal?

SomeHappyFish · Dec 4, 2024

When was the last test before getting a results of 1200ppm ?
20ppm in a day is a test kit usage "error", don't sweat it.

What you are looking for is a trend of the magnesium over time.

"Real magnesium consumption is very low, like 1 ppm per day. It is not more than about 1/10th of the calcium consumption. Anything substantially larger is testing error of some sort."

-Randy Holmes-Farley

KrisReef · Dec 4, 2024

Likely testing challenges for these elements vs actual uptake or loss to the environment

SomeHappyFish · Dec 4, 2024

https://www.reef2reef.com/threads/magnesium-usage.738796/

SomeHappyFish · Dec 4, 2024

alexanderthefishlover said:
Really trying to get more corraline algae growing.

Many reefers actually like not having corraline algae since it's a pain to scrape and it grows everywhere. No harm not having any.

Randy Holmes-Farley · Dec 4, 2024

alexanderthefishlover said:
Hello,

So basically I found my magnesium had dropped to 1200 ppm. I dosed it back to 1340ppm over a course of 3 days.

I left it for a day and just tested and it dropped by 20 ppm in a day? Is this normal? This not a large aquarium and I have soft corals and a few LPS that are not large.

My calcium was at 340 ppm and I’ve got it to 440ppm and that also dropped by 20 ppm in a single day.

I do not have a lot of corraline algae only some on shells and on live rock (want to grow more)m desperately think it’s beautiful!)

I can’t get my hands on a strontium test however I began dosing a small amount the other day. I also began dosing iodide. Really trying to get more corraline algae growing.

Are these drops in magnesium and calcium normal?

Those changes are test error. In most cases, magnesium is not worth testing due to likely errors. Just dose it based on measured calcium consumption.

alexanderthefishlover · Dec 4, 2024

Randy Holmes-Farley said:
Those changes are test error. In most cases, magnesium is not worth testing due to likely errors. Just dose it based on measured calcium consumption.

Sorry can you explain what you mean? So you mean dose it to the same ppm usage as calcium?