Rapid Magnesium Depletion

[ready2get86d]

So this is my first time posting as I can usually find all of the answers i’m looking for in threads but i have something very puzzling going on. My Mag levels are rapidly depleting without any major changes in other perameters.

I waited until i had 5 tests one week apart each with a 10% water change with red sea blue bucket in between each test.

I have a 20g nuvo AIO with an AI Prime 16HD and have softies and lps. Two clowns, and a cardinal, with hermits, tuxedo urchin, and misc snails. Mode of nutrient export is a custom 3D printed turf scrubber which worked wonders for nussience algae in my display and a dino problem i was having. Things seem to survive in my tank but dont seem to grow much (other than kenya tree and gsp)

Week 1:
Salinity - 1.025
Ammonia - 0
Nitrite - 0
Nitrate - 18
Phos - 0.0
PH - 7.6
Calcium - 424
Alkalinity - 8.1
Magnesium - 1400

Week 2: (tried bumping up phos with a little extra reef roids, which always seems to be low)
Salinity - 1.025
Ammonia - 0
Nitrite - 0
Nitrate - 12
Phos - 0.2
PH - 7.7
Calcium - 451
Alkalinity - 8.0
Magnesium - 1292


Week 3: (extra reef roids created a bit of an algae problem even with the turf scrubber)
Salinity - 1.025
Ammonia - 0
Nitrite - 0
Nitrate - 12
Phos - 0.1
PH - 7.6
Calcium - 434
Alkalinity - 8.5
Magnesium - 839 (bought red sea mag and was instructed to dose 40mg over a few days to bring it back up)


Week 4:
Salinity - 1.026
Ammonia - 0
Nitrite - 0
Nitrate - 12
Phos - 0.0
PH - 8.0
Calcium - 484
Alkalinity - 9.0
Magnesium - 1529


Week 5:
Salinity - 1.026
Ammonia - 0
Nitrite - 0
Nitrate - 12
Phos - 0.0
PH - 8.0
Calcium - 460
Alkalinity - 9.0
Magnesium - 1416

As you can see after dosing it dropped more than 100 ppt in a week even after a water change.

From what I’ve seen in threads, it gets blamed on test error, which it isnt because i double checked with two LFS, one of which happens to be WWC. And i don't really have any Coraline, only in little crevices where my urchin cant get to.

Can anyone help me troubleshoot?? I’ll post water tests weekly with any dosing or changes to my routine. If you want any pics just ask.

 

[blaxsun]

You can see a slight variance in testing, as it's impossible to replicate results perfectly every time. If you're seeing a lot of coralline algae growth that's also a magnesium sink, so that could explain some of the consumption.

 

[CoralB]

Agree partly with coralline uptake but I would also highly be concerned with the low and zero phosphates which will lead to issues of Dino’s and your alk is going up which could play a part with the mag going down .which is also why your ph is going up

 

[ready2get86d]

Agree partly with coralline uptake but I would also highly be concerned with the low and zero phosphates which will lead to issues of Dino’s and your alk is going up which could play a part with the mag going down .which is also why your ph is going up

Theres barely any coralline, not enough to consume over 100ppm in a week, and dinos have been gone since the introduction of the turf scrubber. Im wondering if algae growth in the scrubber could be consuming it quickly. I do see the alk going up slowly as the mg is being depleted. But I’m not dosing anything. And red sea blue bucket parameters are 8.0 dkh. Could whatever the consumption of mag is from be causing the alk to rise slowly?

 

[Sean Clark]

This looks like a testing +/- deviation and or testing error. Nothing to worry about Magnesium wise.

 

[CoralB]

You may not have issues with Dino’s now but you really need to get your phosphates up at least to 0.05 - 0.08 . Your algae scrubber will not consume mag but it will consume nitrate and phosphates

 

[ready2get86d]

This looks like a testing +/- deviation and or testing error. Nothing to worry about Magnesium wise.

How greatly can variation in testing be? After i did a one time dose of Mag the next test reflected it.

 

[ready2get86d]

You may not have issues with Dino’s now but you really need to get your phosphates up at least to 0.05 - 0.08 . Your algae scrubber will not consume mag but it will consume nitrate and phosphates

What would you suggest is good way to do this? Without overfeeding

 

[Sean Clark]

How greatly can variation in testing be? After i did a one time dose of Mag the next test reflected it.

That depends on the test but +/- 5% is pretty standard. If you look, your calcium is varying as much as if not more than you magnesium is percentage wise, you can also see the spike where your salinity increases from 1.025 to 1.026 which is normal. The 839 value is defiantly a testing error.

 

[CoralB]

Is your salt that you use properly mixed before you opened it as sometimes either thru manufacturing or shipping it’s makeup could change due to settlement or not being mixed atheist factory and I know myself that I always have to mix my salt before making water . Just a thought

 

[ready2get86d]

That depends on the test but +/- 5% is pretty standard. If you look, your calcium is varying as much as if not more than you magnesium is percentage wise, you can also see the spike where your salinity increases from 1.025 to 1.026 which is normal. The 839 value is defiantly a testing error.

Okay, that possible test deviation % makes me feel a bit better. I’ll update next Friday with the same values and see if there is a downward trend still. Regardless of +/- if its trending down i want to try to get to the bottom of it.

 

[CoralB]

What would you suggest is good way to do this? Without overfeeding

Limit your scrubber time and or dose. Also feeding reef roids always raises mine . Take your pic or all the above

 

[Sean Clark]

Okay, that possible test deviation % makes me feel a bit better. I’ll update next Friday with the same values and see if there is a downward trend still. Regardless of +/- if its trending down i want to try to get to the bottom of it.

As a general rule your mg will only deplete at a rate of 1/10 ca consumption.

 

[ready2get86d]

Is your salt that you use properly mixed before you opened it as sometimes either thru manufacturing or shipping it’s makeup could change due to settlement or not being mixed atheist factory and I know myself that I always have to mix my salt before making water . Just a thought

I take the bag out and tumble it around after i buy a bucket and before mixing to make sure it isn't stratified. Especially now, but good thought! I had read that somewhere a few weeks ago so I didn’t want settled salt mix to potentially skew the test data.

 

[ready2get86d]

Limit your scrubber time and or dose. Also feeding reef roids always raises mine . Take your pic or all the above

I hadn't thought about decreasing light time on the scrubber, thank you! I’ll try turning it down by an hour a week and see how that helps phos consumption.

 

[ready2get86d]

Has anyone else run into this rapid Mag depletion that falls outside of the normal 1/10 of calcium consumption? I have a nagging feeling that the turf scrubber has something to do with it.