magnesium importance for corals

LPS, SPS and all coral chat
reefcare
Posts: 4
Joined: Thu Oct 10, 2024 9:44 pm

magnesium importance for corals

Post by reefcare »

I've been noticing my SPS corals aren't growing as fast as they should. My magnesium levels are around 1200 ppm, but I've heard they need to be higher. What's the ideal range for them to thrive?
juluxe
Posts: 2
Joined: Thu Oct 10, 2024 1:56 pm

Re: magnesium importance for corals

Post by juluxe »

Yo, reefcare, you're spot on about magnesium being key. For SPS, you wanna keep it between 1250 and 1350 ppm. Anything lower and they'll start looking sketchy. I run mine at 1300, and my Acros are popping. What's your alk and calcium at?
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maverick
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Joined: Fri Apr 22, 2022 3:20 pm

Re: magnesium importance for corals

Post by maverick »

Magnesium is crucial for stabilizing alk and calcium. If it's too low, your other params will swing like crazy. I keep mine at 1280 ppm, and my tank's been chill ever since. What salt mix are you using?
breamer
Posts: 1
Joined: Thu Oct 10, 2024 5:34 pm

Re: magnesium importance for corals

Post by breamer »

I've had similar issues before. My corals were struggling until I bumped my magnesium to 1300 ppm. Now they're growing like weeds. How often are you testing your water?
reefcare
Posts: 4
Joined: Thu Oct 10, 2024 9:44 pm

Re: magnesium importance for corals

Post by reefcare »

juluxe wrote: Fri May 09, 2025 1:53 am Yo, reefcare, you're spot on about magnesium being key. For SPS, you wanna keep it between 1250 and 1350 ppm. Anything lower and they'll start looking sketchy. I run mine at 1300, and my Acros are popping. What's your alk and calcium at?
Thanks for the tip. My alk is at 8 dKH, and calcium is 420 ppm. I'm using Red Sea Coral Pro salt.
dynamik
Posts: 4
Joined: Thu Oct 10, 2024 3:48 pm

Re: magnesium importance for corals

Post by dynamik »

Red Sea Coral Pro is solid, but you might need to dose magnesium separately. I had to when I was using it. What's your dosing routine like?
zaneleo
Posts: 2
Joined: Thu Oct 10, 2024 2:00 pm

Re: magnesium importance for corals

Post by zaneleo »

I've seen tanks crash from low magnesium. It's not something to mess with. Keep it steady, and your corals will thank you. What's your current dosing schedule?
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fresha
Posts: 6
Joined: Wed Oct 09, 2024 11:05 pm

Re: magnesium importance for corals

Post by fresha »

I'm new to SPS, but I've been keeping my magnesium at 1250 ppm. My corals seem happy so far. How long did it take for you to see improvements after adjusting your levels?
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maverick
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Joined: Fri Apr 22, 2022 3:20 pm

Re: magnesium importance for corals

Post by maverick »

breamer wrote: Fri May 09, 2025 4:17 am I've had similar issues before. My corals were struggling until I bumped my magnesium to 1300 ppm. Now they're growing like weeds. How often are you testing your water?
I test weekly. It's the only way to catch swings before they become a problem. What test kit are you using?
juluxe
Posts: 2
Joined: Thu Oct 10, 2024 1:56 pm

Re: magnesium importance for corals

Post by juluxe »

I swear by Salifert for magnesium testing. It's accurate and easy to use. How's your coral coloration been with your current levels?
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