Mg 1650+... Reef Crystals

[DeepBlueSeaV1]

Admittedly, of my 3 different systems over the years, I've never tested for Mg. Just never felts like I had any problems with Mg or coral growth.

I just purchased a Salifert Mg Test kit.
1st test, color doesn't change.
2nd test, color doesn't change with full dose of regent 3. re-fill regent 3 syringe again and dose .1 m; more, to see color change from pink to blue.

Suggesting Mg ~1650mg

I don't dose Mg.
I use IO Reef Crystals.

120g tank is only 5 1/2 months old. a few SPS, LPS, zoas. Everything has been growing very nicely. Coralline algae is still ramping up with dime size circles on glass and a finally starting to take hold on some of the rock (it's not a lot by any means in my opinion). Tank is maturing and continues to run it's cycles. 15 gallon every 7 - 10 days, water changes have been being performed religiously.

ATO reservoir is full strength kalkwasser. Evaporation rate is about a gallon and a half a day.

Other tests results this morning. (which I'm really quite pleased with as I've just been away for a week and haven't touched the tank.)

pH 8.2
Calcium - 470
Alkalnity 9.2
Nitrate 2.5
Po4 .03

Just looking to confirm that this Mg reading would be considered "normal" and once I get more hard corals / coralline algae in the system Mg starts reducing.

Thanks

 

[BenitaSolo]

Sorry that I don’t have an answer but I will be tagging along.
I use Fritz pro on two separate 120g tanks and the mg measures right around 1700... i dose alk and calc and no other elements with mag. Glancing around online it appears that it takes very high mag levels to do any damage. However, some local experienced reefers in my area tell me that sps will bleach at a magnesium level of 1700+.
I don’t think that the high magnesium levels are to blame for any problems but I can’t say for sure. I am currently having an issues with severe zoanthid colonies, but it may be linked to something all together differently.

 

[Randy Holmes-Farley Verified Community Expert]

I somewhat doubt magnesium is actually that high if the salinity is 35 ppt, but it is likely OK anyway.

What is the salinity and how did you measure it?

 

[DeepBlueSeaV1]

I somewhat doubt magnesium is actually that high if the salinity is 35 ppt, but it is likely OK anyway.

What is the salinity and how did you measure it?

I was thinking the same, seems to me that would represent a tank over dosing and I'm not dosing at all.

DD Refractometer 1.026 / 35ppt - Double checked calibration against solution. Spot on at 77 degrees.

Just did the Salifert Mg test again, took one or two more drops than 1ml of regent 2 to change the color from pinkish hue to blue.

Maybe running closer to 1500 without dosing at this point in time.

 

[Randy Holmes-Farley Verified Community Expert]

I was thinking the same, seems to me that would represent a tank over dosing and I'm not dosing at all.

DD Refractometer 1.026 / 35ppt - Double checked calibration against solution. Spot on at 77 degrees.

Just did the Salifert Mg test again, took one or two more drops than 1ml of regent 2 to change the color from pinkish hue to blue.

Maybe running closer to 1500 without dosing at this point in time.

I wouldn't worry about it one way or the other.