Calcium and magnesium help

bmorris03

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Hey everyone this is my first post. I started my 50 gallon IM lagoon at the end of November. I started testing my alk, calcium, and magnesium on December 23. My alk started about 11.9dkh, my calcium started at around 290ppm, and my magnesium was at 1100ppm. I figured I’d do water changes and see my calcium and magnesium come up and my alk come down. I test weekly and my alk has dropped to 10.7dkh. My calcium rose to 325ppm but then dropped to 320ppm, and my magnesium rose to 1150ppm but then fell down to 1050ppm. I’m mixing my salt to 1.025 using Fritz RPM. Btw I started the tank using water from a LFS. Is this something that I should just keep doing water changes and it’ll eventually level out or do I need to dose? I change 5 gallons of water out each week which comes out to a little over 10%.

Other levels:
Ammonia:0
Nitrite:0
Nitrate:2ppm
Phosphate:0
PH:8.2

Livestock:
2 clowns
1 tomini
1 cleaner shrimp
1 fire shrimp
1 watchman goby/pistol shrimp pair
10 blue leg hermit crabs
No corals yet

IMG_0563.jpeg
 

tbrown

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It could be as simple as settling in the bag/box/bucket. If it's a bucket, roll it on the floor some to stir it up. If it's a bag or a box, stir it with your hands or the scoop. Some elements can settle out and make the mixes uneven.
 
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bmorris03

bmorris03

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It could be as simple as settling in the bag/box/bucket. If it's a bucket, roll it on the floor some to stir it up. If it's a bag or a box, stir it with your hands or the scoop. Some elements can settle out and make the mixes uneven.
Oh okay I appreciate it. I’ll definitely give that a try.
 
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gbroadbridge

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Hey everyone this is my first post. I started my 50 gallon IM lagoon at the end of November. I started testing my alk, calcium, and magnesium on December 23. My alk started about 11.9dkh, my calcium started at around 290ppm, and my magnesium was at 1100ppm. I figured I’d do water changes and see my calcium and magnesium come up and my alk come down. I test weekly and my alk has dropped to 10.7dkh. My calcium rose to 325ppm but then dropped to 320ppm, and my magnesium rose to 1150ppm but then fell down to 1050ppm. I’m mixing my salt to 1.025 using Fritz RPM. Btw I started the tank using water from a LFS. Is this something that I should just keep doing water changes and it’ll eventually level out or do I need to dose? I change 5 gallons of water out each week which comes out to a little over 10%.

Other levels:
Ammonia:0
Nitrite:0
Nitrate:2ppm
Phosphate:0
PH:8.2

Livestock:
2 clowns
1 tomini
1 cleaner shrimp
1 fire shrimp
1 watchman goby/pistol shrimp pair
10 blue leg hermit crabs
No corals yet

IMG_0563.jpeg

I suspect that your salinity is low. How are you measuring salinity, and how did you calibrate?

Keep in mind that hobby Calcium tests are typically only accurate to about 30ppm anyway, so ignore any variation between tests less than that.

You can ignore Magnesium.
 
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Ron Reefman

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Calibrating your refractometer with RODI isn't the most accurate way to do it, but you should be close and maybe reading a bit low. They make 'calibration solutions' you can buy which are more accurate.

What are you using to test Ca, alk and Mg? BTW, the acceptable range for Mg is huge and it should only go down very slowly, even in a fairly heavily stocked tank. API kits should work OK. I use Salifert and have API kits as a backup if I ever get a reading that is WAY OFF after 2 tries with the Salifert kit (very rarely happens). I started using Salifert for Mg because API doesn't make one.

I have a 40g aio setup and I dose Ca and alk every day. It takes me a couple of minutes, so it's not a big deal. I end up testing my salinity, Ca and alk once a week. About 9 times out of 10, my levels are just about right where I want them. I dose 40 to 50ml of Ca (Randy's receipe #2) and 25 to 30ml of alk (again, Randy's receipe #2). If my weekly testing shows one of my levels a bit further out of line than I want, I adjust my dosing during the next week.

This is from 6 months ago when the tank was only a few months old.

20240405_172904.jpg
 
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bmorris03

bmorris03

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Calibrating your refractometer with RODI isn't the most accurate way to do it, but you should be close and maybe reading a bit low. They make 'calibration solutions' you can buy which are more accurate.

What are you using to test Ca, alk and Mg? BTW, the acceptable range for Mg is huge and it should only go down very slowly, even in a fairly heavily stocked tank. API kits should work OK. I use Salifert and have API kits as a backup if I ever get a reading that is WAY OFF after 2 tries with the Salifert kit (very rarely happens). I started using Salifert for Mg because API doesn't make one.

I have a 40g aio setup and I dose Ca and alk every day. It takes me a couple of minutes, so it's not a big deal. I end up testing my salinity, Ca and alk once a week. About 9 times out of 10, my levels are just about right where I want them. I dose 40 to 50ml of Ca (Randy's receipe #2) and 25 to 30ml of alk (again, Randy's receipe #2). If my weekly testing shows one of my levels a bit further out of line than I want, I adjust my dosing during the next week.

This is from 6 months ago when the tank was only a few months old.

20240405_172904.jpg
I’ll look into getting some calibration solution and I’m using salifert for all my test. The tank looks awesome btw!
 
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Randy Holmes-Farley

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I agree that salinity is very likely low, and the bouncing values, such as magnesium dropping 100 ppm, are either testing error or salinity changes, not real consumption.
 
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gbroadbridge

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Im measuring with a refractometer. I calibrated it with rodi water. This is my first tank and I’m testing with salifert.

If you're using Salifert your numbers should be in the ballpark.

Calibrating a refractometer using RODI is not a good idea, especially if the device is designed for saltwater brine rather than seawater.

Almost certainly your salinity is very low, so perhaps check your refractometer against a known good source or buy/make a calibration solution before making any adjustments.
 
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Ron Reefman

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I wouldn't worry about nitrate or phosphate levels at this point in your tanks trip to maturity. I only test for ammonia, nitrite, nitrate & phosphate if I have a bloom of new algae.

I don't know how you do your testing, but here are 2 recommendations: 1) Try to do them at roughly the same time of day. I do mine on Monday mornings after breakfast. 2) Be as careful as you can to try and do measurements during testing and cleaning of test equipment when done.

And thanks for the 'awesome' tank compliment. I guess I should try and get a new photo as I have 5 Black Widow BTA and some good coral growth since that photo was taken!
 
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