DIY 2(3) part order of operations question

[Memisis]

Randy & Reef2Reef Community,

I came across your gem of an article on reefkeeping.com. (This one) I feel that I have digested it after reading numerous times and I am really looking forward to starting this process.

My question is specific to the magnesium dosing. The article says to dose 2.5 cups after dosing 1 gallon of each of the parts 1&2. If the magnesium is needed to prevent calcium and carbonate precipitating to calcium carbonate, why do we not dose the magnesium along with the other parts at a rate of 7.8% to both calc and alk, instead of waiting to dump in 591 ml at once?

I ask because I'm lazy and want to prevent as much calcium carbonate build up as possible inside the tank!

I would think that if the biology in the tank was consuming the magnesium while we are also dosing calc and alk, that we would want to steadily dose the mag to ensure that the water has a constant level of mag to prevent calcium carbonate.

It seems that everything else we dose we do at a steady rate over time in order to prevent swings in nutrients. Why is it different in the case of magnesium?

Cups
2.5 cups Mag, 16 cups calc, 16 cups alk = 1.25/16 7.8% Mag to part 1&2
ML
591.25 ml Mag, 3,784 ml Calc, 3,784 ml Alk = 591.25/7,568 = 7.8% Mag to part 1&2

Looking forward to your feedback on this! Thanks,

 

[laverda]

You can defiantly dose it with the ALK and Ca just allow time between adding each for them to mix thourghly before adding the next one.

 

[Randy Holmes-Farley Verified Community Expert]

Randy & Reef2Reef Community,

I came across your gem of an article on reefkeeping.com. (This one) I feel that I have digested it after reading numerous times and I am really looking forward to starting this process.

My question is specific to the magnesium dosing. The article says to dose 2.5 cups after dosing 1 gallon of each of the parts 1&2. If the magnesium is needed to prevent calcium and carbonate precipitating to calcium carbonate, why do we not dose the magnesium along with the other parts at a rate of 7.8% to both calc and alk, instead of waiting to dump in 591 ml at once?

I ask because I'm lazy and want to prevent as much calcium carbonate build up as possible inside the tank!

I would think that if the biology in the tank was consuming the magnesium while we are also dosing calc and alk, that we would want to steadily dose the mag to ensure that the water has a constant level of mag to prevent calcium carbonate.

It seems that everything else we dose we do at a steady rate over time in order to prevent swings in nutrients. Why is it different in the case of magnesium?

Cups
2.5 cups Mag, 16 cups calc, 16 cups alk = 1.25/16 7.8% Mag to part 1&2
ML
591.25 ml Mag, 3,784 ml Calc, 3,784 ml Alk = 591.25/7,568 = 7.8% Mag to part 1&2

Looking forward to your feedback on this! Thanks,

It is certainly fine to spread out magnesium dosing into as many small doses as you like. Smaller cannot be worse, just more work,.

In general, I do not know of any biological process that is magnesium limited in a reef tank, and so some variation in magnesium is unlikely to be any concern, and the real consumption rate is so very low, that in a week magnesium is unlikely to change by more than one percent. We cannot even measure alkalinity or calcium that accurately.

 

[Memisis]

It is certainly fine to spread out magnesium dosing into as many small doses as you like. Smaller cannot be worse, just more work,.

In general, I do not know of any biological process that is magnesium limited in a reef tank, and so some variation in magnesium is unlikely to be any concern, and the real consumption rate is so very low, that in a week magnesium is unlikely to change by more than one percent. We cannot even measure alkalinity or calcium that accurately.

Thanks for your reply! I only did a little searching but could not find anything related to reef tanks consuming mag, I guess as a nutrient for biology its used at a trace rate. So your comment makes total sense.

Thanks again,

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for your reply! I only did a little searching but could not find anything related to reef tanks consuming mag, I guess as a nutrient for biology its used at a trace rate. So your comment makes total sense.

Thanks again,

The relative consumption rate is about:

2.8 dKH of alkalinity
18-20 ppm calcium
0-2 ppm magnesium

Thus, if you deplete alk at a rate of 21.5 dKH per day, in a week you will deplete at most about 14 ppm pf magnesium, which is only about 1% of the total magnesium present.