Talk to me about Magnesium

[Dustin07]

back in the day I never had to test or supplement for Mag or Calcium. I never lost any corals and never thought about it. Now with my 10g nano I'm running, I'm getting pickier with my corals and really want to see how healthy I can get them, as well as how much I can get them to spread.

So.. I grab some magnesium. read the directions and realize, I have no idea how much to supplement until I test.
I get a tester, follow the directions to the T and as far as I can tell, it indicates I have zero magnesium reading in my tank. like literally zero?
So I again consult the magnesium supplement to see how much I should be adding.

It's a lot. like half the bottle, if my test results are accurate.
That seems weird to me.

Can anyone help direct me a bit in magnesium dosing, calcium, Ph, and their relations? My water does at time test high for Ph and I treat for that.

 

[kharmaguru]

back in the day I never had to test or supplement for Mag or Calcium. I never lost any corals and never thought about it. Now with my 10g nano I'm running, I'm getting pickier with my corals and really want to see how healthy I can get them, as well as how much I can get them to spread.

So.. I grab some magnesium. read the directions and realize, I have no idea how much to supplement until I test.
I get a tester, follow the directions to the T and as far as I can tell, it indicates I have zero magnesium reading in my tank. like literally zero?
So I again consult the magnesium supplement to see how much I should be adding.

It's a lot. like half the bottle, if my test results are accurate.
That seems weird to me.

Can anyone help direct me a bit in magnesium dosing, calcium, Ph, and their relations? My water does at time test high for Ph and I treat for that.

I would say that impossible unless you used table salt to fill your aquarium ( I know you didn't). What are you using to test?

 

[Dustin07]

ahaha no, no table salt. my corals seem to be thriving and my zooas are already spreading a little bit. only negative in my tank is another brown diatom (sp?) bloom but it's nowhere near as bad as the last one. likely from me over supplementing but...

this is the kit I picked up

AF Magnesium Test Kit

Quickly and accurately measure the Magnesium concentration in saltwater aquariums! Every test kit batch is certified and approved by Aquaforest ICP-OES testing reference solutions. Recommended Magnesium Level - 1260ppm - 1500ppm Aquaforest marine test kits are designed to quickly and...

www.bulkreefsupply.com

 

[kharmaguru]

ahaha no, no table salt. my corals seem to be thriving and my zooas are already spreading a little bit. only negative in my tank is another brown diatom (sp?) bloom but it's nowhere near as bad as the last one. likely from me over supplementing but...

this is the kit I picked up

AF Magnesium Test Kit

Quickly and accurately measure the Magnesium concentration in saltwater aquariums! Every test kit batch is certified and approved by Aquaforest ICP-OES testing reference solutions. Recommended Magnesium Level - 1260ppm - 1500ppm Aquaforest marine test kits are designed to quickly and...

www.bulkreefsupply.com

I haven't used that one but it's titration so I assume you are waiting for a colour change while adding drops. You're saying the colour changes immediately?

 

[mtnbike101]

FWIW, about every four to six months, I send in a water sample to ATI or Triton just to be sure my test kits are valid and also to get values on things for which I cannot test.

Magnesium is one I wouldn't worry too much about. Don't get me wrong, it is important, but not like KH, pH or Ca.

 

[Dustin07]

I haven't used that one but it's titration so I assume you are waiting for a colour change while adding drops. You're saying the colour changes immediately?

I wouldn't say immediately but yes sorta. If I understand the syringe correctly then once the water changes to blue you flip it over to see how much is still in the syringe. in my case, the syringe is still so full that it doesn't even read on the spectrum as having mag..

but again, first time testing for magnesium so I could be really confused.

if I understand correctly, the more drops I have to add to change color, the more magnesium that is in the water correct?

FWIW, about every four to six months, I send in a water sample to ATI or Triton just to be sure my test kits are valid and also to get values on things for which I cannot test.

Magnesium is one I wouldn't worry too much about. Don't get me wrong, it is important, but not like KH, pH or Ca.

that's what I'm hearing more and more, I'll be doing calcium testing next.

 

[kharmaguru]

if I understand correctly, the more drops I have to add to change color, the more magnesium that is in the water correct?

yes.

 

[blowmecius]

That test kit comes with a reference solution. Use it instead of tank water to see if your results are closer to what should be expected. If not test is defective or you are doing something wrong.

Use this calculator to determine amount to dose:

Reef Chemistry Calculator

It takes a lot of supplement to raise magnesium.

Magnesium affects the amount of calcium and alkaline that will stay in solution without precipitating. Too low and you can’t maintain calcium/alkalinity.

 

[Dustin07]

ahh very helpful, thank you! I'll give it another go tonight

 

[Dustin07]

So my original test indicated zero magnesium in my tank. the amount of Mag I was supposed to add seemed ridiculous so I opted to opted to dose only the half recommended amount and wait a few days.

I tested again, and got a reading finally however the reading on my second test, post mag dosage (half recommended) indicated that my original test at 0 mag was probably pretty dang accurate!

either way, since dosing with mag it seems like my tank is on steroids. My zooas are the most open and healthy looking I have ever seen, pretty excited about that!