Mag???

[rdnelson99]

Had my water tested at an LFS who I trust because (too late) I found out the API tests were not the best. I mostly wanted to see calcium. My test from the same sampe read 440 while the lfs read 400. Not great but not bad. She did however say my mag. was a bit low (1250) and mag is required by corals to enable them to process the calcium.

Questions:

1. What level is preferred for Mag.
2. Is her statement about it helping the corals process the calcium accurate?
3. Other than dosing is there any good way to raise mag?
4. If dosing is required, what would you suggest?

As always, thanks so much for all the help.

 

[ccCapt]

1- Magnesium should be between 1250-1350 ppm.
Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com
2- When a hard coral builds it's calcium carbonate skeleton, it uses aprox 18 ppm calcium, 2.8 dKH alk and 2 ppm mag. If either of the 3 are too low (calcium less than 380, alk less than 7 dKH or mag less than 1250) the calcification process will be inhibited.
3- Dosing is really the only way to raise mag.
4- Epsom salts or a combination of epsom salts (magnesium sulfate) and magnesium chloride.
Do-It-Yourself Magnesium Supplements for the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

 

[jtrasap]

1250 is at the bottom end of just fine for Mag. Yes, mag is taken up by corals and plays many roles in a reef tank. Most people try to keep mag between 1250-1350, if it gets much below 1250 you may have issues with calcium and carbonate precipitating out. With regular water changes most people don't have problems keeping Mag up. 44o is also just fine for calcium as on average Natural seawater runs around 420 ppm calcium.

 

[rdnelson99]

Thanks guys. I appreciate the input. Helps me to understand it a bit better.

 

[spideybry]

1250 is at the bottom end of just fine for Mag. Yes, mag is taken up by corals and plays many roles in a reef tank. Most people try to keep mag between 1250-1350, if it gets much below 1250 you may have issues with calcium and carbonate precipitating out. With regular water changes most people don't have problems keeping Mag up. 44o is also just fine for calcium as on average Natural seawater runs around 420 ppm calcium.

I agree with everything that people say so far. Only thing I would say is to check your salt. Some salts come low in certain levels while others come high in others. One example would be Oceanic salt which comes in at around 1600ppm for mag, while Crystal Sea Marinemix comes in at 1200ppm.

So, if you are conducting your water changes regularly, and don't see a change, I would run a test on a batch of fresh salt water to see what your levels are at for calc, alk, and mag, then dose accordingly.

 

[rdnelson99]

I do a 10% PWC every weekend. I make my own RO/DI water and use Instant Ocean Salt mix. Once I get a few more corals going and use up what I have on hand, I may change to the Reef Crystals. It is my understanding it is better suited for corals while the standard salt mix would be better for a FOWLR. Would that be a safe assumption?

 

[carey]

That's what I did. i switched over from regular I/O to reef crystals once I got a bunch of corals. Although now I;m having high calcium and low alaklinity issues...all happened when I switched. or it could be all the corals I now have LOL

 

[ccCapt]

I do a 10% PWC every weekend. I make my own RO/DI water and use Instant Ocean Salt mix. Once I get a few more corals going and use up what I have on hand, I may change to the Reef Crystals. It is my understanding it is better suited for corals while the standard salt mix would be better for a FOWLR. Would that be a safe assumption?

No, I would not make that assumption. I know of quite a few successful reef tanks that use regular IO. Typically IO mixes to 400 calcium, 11 dKH alk and 1350 mag. All perfectly fine numbers. Reef Crystals is considerably higher in all 3 (490, 13, 1440) but the higher number are of no advantage to coral growth. RC also contains some kind of vitamins, but no one knows what they are or what they supposedly do.

Here are 2 local tanks that use IO.

 

[rdnelson99]

No, I would not make that assumption. I know of quite a few successful reef tanks that use regular IO. Typically IO mixes to 400 calcium, 11 dKH alk and 1350 mag. All perfectly fine numbers. Reef Crystals is considerably higher in all 3 (490, 13, 1440) but the higher number are of no advantage to coral growth. RC also contains some kind of vitamins, but no one knows what they are or what they supposedly do.

Here are 2 local tanks that use IO.

First I just have to say "WOW!!!" Nice tanks.

Second, thanks for the info. I had not really looked into it yet because I have a bunch of IO that will last me a while. That is good info.

 

[ksl1972]

Im using the coral pro salt from redsea. It has always tested spot on for cal mag and alk with RO/di water. The way the LFS explained to me about mag is. Mag keeps the alk and cal apart so the corals can us it. I was told never to add alk or cal at the same time because the will combine and make a mess. And to add my alk to my top of water because it is removed by to RO/di unit. If I add mag of cal I add it will a drip system so not to shock my tank.