Ideal magnesium for LPS corals

LPS, SPS and all coral chat
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Florion
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Ideal magnesium for LPS corals

Post by Florion »

Been running my tank at 1250 ppm magnesium for a while now, but my LPS seem kinda sluggish. What's the sweet spot for these guys? Got a 40 gallon with two clowns, weekly 10% water changes, and running a Reef Octopus skimmer.
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zenwave9
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Re: Ideal magnesium for LPS corals

Post by zenwave9 »

1250's a bit low for most LPS. I keep mine at 1350–1400, and they're thriving. What's your calcium and alk at? If those are off, it won't matter much what your mag is. Also, what salt mix are you using? Some are way off on mag out of the box.
Skytorch
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Joined: Thu Oct 10, 2024 7:37 pm

Re: Ideal magnesium for LPS corals

Post by Skytorch »

Yep, zenwave9's got it right. I bumped mine to 1400 last month, and my Hammers started extending way more. Running Red Sea Coral Pro salt, which mixes around 1350, so I dose a bit extra. You got any Acans or Torches in there? They're usually the first to show mag issues.
trevo
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Re: Ideal magnesium for LPS corals

Post by trevo »

Skytorch wrote: Thu Jun 05, 2025 2:01 am Yep, zenwave9's got it right. I bumped mine to 1400 last month, and my Hammers started extending way more. Running Red Sea Coral Pro salt, which mixes around 1350, so I dose a bit extra. You got any Acans or Torches in there? They're usually the first to show mag issues.
Funny you mention that, my Acans were super closed up until I fixed my mag. Now they're puffier than my cat after a nap. What test kit are you using, Florion? Some of the cheaper ones can be sketchy with mag readings.
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corals
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Re: Ideal magnesium for LPS corals

Post by corals »

My mag's at 1300, but my Duncan's still happy. Dunno if it's the mag or just luck. Got a 20 gallon with a HOB filter, no skimmer. Maybe smaller tanks are more forgiving?
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Florion
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Re: Ideal magnesium for LPS corals

Post by Florion »

Thanks for the tips, everyone. Gonna bump it up to 1350 and see how they react. Using Salifert for testing, by the way. Appreciate the help!
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zenwave9
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Re: Ideal magnesium for LPS corals

Post by zenwave9 »

Florion wrote: Thu Jun 05, 2025 6:43 am Thanks for the tips, everyone. Gonna bump it up to 1350 and see how they react. Using Salifert for testing, by the way. Appreciate the help!
Salifert's solid. Just go slow with the adjustments—no more than 50 ppm per day. And keep an eye on your alk, 'cause mag dosing can sometimes throw it off. What's your lighting schedule like? Low light can make LPS look sluggish too.
Skytorch
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Re: Ideal magnesium for LPS corals

Post by Skytorch »

True about the light. I run mine 8 hours with a 2-hour ramp. Also, if you're dosing mag, make sure it's not the kind with extra sulfate. Some brands add it, and it can mess with your bacteria. Had that happen once, and my tank got all cloudy.
trevo
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Re: Ideal magnesium for LPS corals

Post by trevo »

Cloudy tanks are the worst. Had a bacterial bloom last year from overdoing it with amino acids. Took weeks to clear up. But back to mag—anyone tried the ESV B-Ionic mag supplement? Heard it's pretty clean.
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corals
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Re: Ideal magnesium for LPS corals

Post by corals »

Nope, just using the Brightwell stuff. Works fine for me. But my tank's tiny, so I don't need much. You guys with big systems probably know better.
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