Why bother with magnesium when using the BRS "2-Part"?

[Dom]

Good morning,

I have been dosing the BRS 2-part via an automated dosing system for 3 weeks. But I have yet to touch the Mg that I've mixed.

I've read several times where it has been suggested not to test Mg, and as hobbyists, we only need to be concerned with the presence of Mg as it is an indicator of something more important going on.

Today, I read in a post that the amount of Mg supplement dosed is related to the amount of Ca dosed. I'm sure this ins't the first time it has been mentioned, just the first time I've read it.

I'm currently dosing 24ml Ca daily. This means I should dose daily, 1.2 - 2.4 ml of Mg daily, regardless of the tested number?

Thank you,
Dom

 

[sfin52]

Good morning,

I have been dosing the BRS 2-part via an automated dosing system for 3 weeks. But I have yet to touch the Mg that I've mixed.

I've read several times where it has been suggested not to test Mg, and as hobbyists, we only need to be concerned with the presence of Mg as it is an indicator of something more important going on.

Today, I read in a post that the amount of Mg supplement dosed is related to the amount of Ca dosed. I'm sure this ins't the first time it has been mentioned, just the first time I've read it.

I'm currently dosing 24ml Ca daily. This means I should dose daily, 1.2 - 2.4 ml of Mg daily, regardless of the tested number?

Thank you,
Dom

Mag is used much much slower than alk and calcium. If your doing water changes that may be enough to supplement mag

 

[BeanAnimal]

Mag is used much much slower than alk and calcium. If your doing water changes that may be enough to supplement mag

That is not typically going to work.

@Dom it is not equal volumes that you need to dose, but equivalent concentrations to keep things balanced. You need to use one of the many available calculators to determine what "balanced" is with regard to the concentrations of your Ca and Mg solutions.

 

[Dom]

Mag is used much much slower than alk and calcium. If your doing water changes that may be enough to supplement mag

Yes, I rely on water changes to replenish elements on my smaller tanks. But the total volume on this tank is 145 gallons. While 30 gallons weekly is doable, I decided to dose instead.

 

[Dom]

That is not typically going to work.

@Dom it is not equal volumes that you need to dose, but equivalent concentrations to keep things balanced. You need to use one of the many available calculators to determine what "balanced" is with regard to the concentrations of your Ca and Mg solutions.

Yes. I use this calculator: https://reef.diesyst.com/chemcalcnew.html

It would make sense to me that the amount of Mg to dose would automatically be calculated based on the Ca numbers you input. Am I using the calculator wrong?

 

[Randy Holmes-Farley]

Good morning,

I have been dosing the BRS 2-part via an automated dosing system for 3 weeks. But I have yet to touch the Mg that I've mixed.

I've read several times where it has been suggested not to test Mg, and as hobbyists, we only need to be concerned with the presence of Mg as it is an indicator of something more important going on.

Today, I read in a post that the amount of Mg supplement dosed is related to the amount of Ca dosed. I'm sure this ins't the first time it has been mentioned, just the first time I've read it.

I'm currently dosing 24ml Ca daily. This means I should dose daily, 1.2 - 2.4 ml of Mg daily, regardless of the tested number?

Thank you,
Dom

The BRS recipe is my DIY (they asked me if they could use it).

The magnesium is recommended to be added independent of measurement of mag. BRS states that as well.

1 mL of the mag part for each 6.2 ml of the calcium part. (610 mL or each gallon of calcium part)

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

 

[BeanAnimal]

Yes, I rely on water changes to replenish elements on my smaller tanks. But the total volume on this tank is 145 gallons. While 30 gallons weekly is doable, I decided to dose instead.

You typically can't maintain levels with water changes alone, even with modest elevated levels in the change water.