Quick question...

[RobW]

Just measured my calc, all, and mag.

Cal 425
Alk 9
Mag 1580

Magnesium seems high, right? Should be somewhere in the 1200-1300 ish range right?

What are some safe steps to reduce that? Just water change or adjust something?

 

[Brasileiro561]

I would base this off your corals. Each tank is different. But as long as it’s stable and everything looks happy you should be ok. I for example had my alk at 8 calcium at 550 right and mag at 1450 for a long time and everything was doing fine. I don’t know how My mag got so high since I never dose mag.

 

[Randy Holmes-Farley Verified Community Expert]

Just measured my calc, all, and mag.

Cal 425
Alk 9
Mag 1580

Magnesium seems high, right? Should be somewhere in the 1200-1300 ish range right?

What are some safe steps to reduce that? Just water change or adjust something?

Red Sea magnesium kit? Many people have problems with it.

Try the kit on some new salt water (what brand?).

 

[RobW]

Red Sea magnesium kit? Many people have problems with it.

Try the kit on some new salt water (what brand?).

yes red sea.

 

[Brandon Smith]

What salt are you using. I know IO runs high. But, you typically want magnesium at 1440 ppm.

 

[RobW]

What salt are you using. I know IO runs high. But, you typically want magnesium at 1440 ppm.

brightwell neo-marine

 

[RobW]

I'm not having any issues with any corals or anything else in the tank. Corals are actually growing very well right now. My clam is also doing well. Currently in the tank I Have the following: I did some small water changes through the week. Going to do another small water change today and retest again. I have had no other tank mates have problems.

1 Eagle Eye Zoa (20+ polyps)
1 Red Hornet Zoa (18 polyps)
1 Utter Chaos Zoa frag (3 polyps)
1 Jungle Juice Zoa (12 polyps)
1 Red Montipora Capricornis roughly 8" x 3-1/2"
1 Purple Torch about the size of a fist when fully open
1 purple long tentacle anemone about the size of a fist
1 Green Star Polyp about 3" round
1 Blue Rimmed Derasa Clam
1 Purple Pincushion Urchin
4 Trochus Snails
4 Turbo Snails
1 Fire Shrimp
1 Red Fire Goby
2 Green Chromis
12 Pacific Red Legged Hermit Crabs

 

[Randy Holmes-Farley Verified Community Expert]

What salt are you using. I know IO runs high. But, you typically want magnesium at 1440 ppm.

Why so high? IMO, a level matching 35 ppt seawater at 1280 ppm is fine.

 

[Brandon Smith]

Why so high? IMO, a level matching 35 ppt seawater at 1280 ppm is fine.

Honestly it is just because that is what I have read from other sources browsing around and what WWC shoots for. I used to use IO Reef Crystals, and it always runs over 1600 ppm.

 

[Randy Holmes-Farley Verified Community Expert]

Honestly it is just because that is what I have read from other sources browsing around and what WWC shoots for. I used to use IO Reef Crystals, and it always runs over 1600 ppm.

Reef Crystals should not be that high, last I saw. Maybe your kit is off or the salinity is a bit high.

 

[Brandon Smith]

Reef Crystals should not be that high, last I saw. Maybe your kit is off or the salinity is a bit high.

What test kit do you recommend for magnesium? I have been using Red Sea lately.

 

[RobW]

Reef Crystals should not be that high, last I saw. Maybe your kit is off or the salinity is a bit high.

so higher salinity contributes to higher magnesium levels?

 

[RobW]

right now, my salinity is 1.024 measured with a refractometer

 

[RobW]

i just checked the magnesium. im now sitting at 1400. so i either made an error while testing or the water changes brought it back down.

 

[Randy Holmes-Farley Verified Community Expert]

so higher salinity contributes to higher magnesium levels?

Yes, 1200 ppm at sg = 1.024 will rise to 1300 ppm at sg = 1.026.

Everything rises (except ORP and pH) the same proportion, but magnesium is very high to begin with so has a big absolute rise.

 

[Keen4]

What test kit do you recommend for magnesium? I have been using Red Sea lately.

Same! I use Red Sea and Salifert and I always get a really super high number from Red Sea even with doing multiple tests one after another.

 

[Brandon Smith]

@Dana Riddle, I know you are a very busy man. Do you have a list of test kits that you prefer to use? I know I can count on your information to be unbiased.

 

[Dana Riddle]

@Dana Riddle, I know you are a very busy man. Do you have a list of test kits that you prefer to use? I know I can count on your information to be unbiased.

I was the manager of a wet lab when I was in Hawaii, and it was stocked with equipment from Hach. Most of their tests are EPA-approved for use with seawater. I invested in a Hach colorimeter, digital titrator, heater block, and HQ40d multi-meter to test for:
Alkalinity
Ammonia
Calcium
Iron, Total
Iron, Ferrous
Iron, Ferric (by calculation)
Magnesium (by calculation)
Nitrate (approved if corrections are applied)
Nitrite
Phosphate, ortho-
Phosphate, total (requires digestion)
Phosphate, acid-hydrolyzable (requires digestion)
Dissolved oxygen (HQ40d)
pH (HQ40d)
Temperature
I also have the Hanna Checkers for alkalinity, calcium, phosphorus, and iron. These produce results that compare favorably to the expensive Hach equipment.
At one time, Instant Ocean marketed comparators that used Hach reagents. Not sure if they still do.
I've used Salifert's alkalinity test - its results were favorable to the titration method.
I use the Red Sea potassium test. A lengthy test but it reports numbers that are at least ballpark hence I tend to trust it.
For specific gravity, a refractometer is the way to go, IMO.

 

[Luckyduck]

I was the manager of a wet lab when I was in Hawaii, and it was stocked with equipment from Hach. Most of their tests are EPA-approved for use with seawater. I invested in a Hach colorimeter, digital titrator, heater block, and HQ40d multi-meter to test for:
Alkalinity
Ammonia
Calcium
Iron, Total
Iron, Ferrous
Iron, Ferric (by calculation)
Magnesium (by calculation)
Nitrate (approved if corrections are applied)
Nitrite
Phosphate, ortho-
Phosphate, total (requires digestion)
Phosphate, acid-hydrolyzable (requires digestion)
Dissolved oxygen (HQ40d)
pH (HQ40d)
Temperature
I also have the Hanna Checkers for alkalinity, calcium, phosphorus, and iron. These produce results that compare favorably to the expensive Hach equipment.
At one time, Instant Ocean marketed comparators that used Hach reagents. Not sure if they still do.
I've used Salifert's alkalinity test - its results were favorable to the titration method.
I use the Red Sea potassium test. A lengthy test but it reports numbers that are at least ballpark hence I tend to trust it.
For specific gravity, a refractometer is the way to go, IMO.

Hey Dana.
I am looking at buying a Hanna Iron tester. Seeing that we are looking at such small numerical values in saltwater aquariums in your opinion would it be smarter to buy the Low range iron checker and just convert PPB to PPM or will the standard checker suffice? Reagents are over double the cost on the Low range checker but it seems like that would work much better for reading low amounts. What's your take?

 

[Randy Holmes-Farley Verified Community Expert]

Hey Dana.
I am looking at buying a Hanna Iron tester. Seeing that we are looking at such small numerical values in saltwater aquariums in your opinion would it be smarter to buy the Low range iron checker and just convert PPB to PPM or will the standard checker suffice? Reagents are over double the cost on the Low range checker but it seems like that would work much better for reading low amounts. What's your take?

IMO, no kit or checker for iron is really needed or useful for routine husbandry as none can detect as low as NSW levels and there is no reason to keep it higher. Even ICP cannot detect NSW surface levels of iron. ICP can barely detect the iron when I first dose it, and then later it cannot even if it is way above NSW levels (which can be only 0.000006 ppm.

This is from one of my articles on my ICP results:

My Triton Testing Results: By Randy Holmes-Farley - REEFEDITION

Recently, Triton GmbH in Germany has initiated a method of testing many ions at once for a single price. In the US, that service is coordinated by Unique Corals. For $49 they will send you a couple of tubes to collect a tank water sample, and a prepaid mailer to send the sample back to them...

www.reefedition.com

Iron (Fe). The natural iron level varies a lot with depth, but surface seawater may have only 0.006 µg/L. The Triton LOD = 0.3 µg/L. I dose iron, and when I dose it I boost iron to roughly 1-2 µg/L, which would be detectable. This sample was taken more than a week after the last iron dosing, and none was detected as it gets depleted in the meanwhile. I’ve not yet seen a Triton test result for a real aquarium sample that had detectable iron, but that doesn’t mean these tanks are necessarily deficient. Iron is also a case where the form is critical, and ICP cannot distinguish form. Binding to organic matter, for example, can alter the bioavailability of iron.