Manganese dosing

dodgy67 · 03/07/2020, 10:24 AM

Read an article recently where Randy commented that Manganese is 28% by weight, I have just received a packet of Manganese (ll) Chloride Tetrahydrate 98% assume this is not 98% Manganese before I recalculate dosing.

Thanks in advance for any advice.

bertoni · 03/07/2020, 07:31 PM

Let's go through the math. Manganese chloride is MnCl₂. The molecular mass of the Cl part is 71.0. The Mn part is about 55. H₂O has a molecular mass of 18, and this is a tetra-hydrate, so the water part is 4 * 18 or 72. The mass per molecule is thus 198, of which 55 units are manganese, which leads to about 28% manganese by weight. To dose 1 ppm, which is about 1 mg/L, lets just say 4 mg/L of your manganese product, since 28% is close enough to 25%.

What kind of scale or measuring equipment do you have on hand?

dodgy67 · 03/08/2020, 04:40 AM

This was the original thread I was following
Following this recipe by @Randy Holmes-Farley

Manganese(II) chloride tetrahydrate is 28% manganese by weight.
Here's a recipe:

Dissolve 1 gram in 100o mL (grams) fresh water. Manganese = 280 ppm.
Take 1 mL (1 g) of that mix and dissolve in 1000 mL of fresh water. Mn = 0.28 ppm (=280 ug/L).
Add 1 mL of that to 100 mL of fresh water. Mn = 2.8 ug/L
Add 13.5 mL of that to 100 gallons of tank water. Conc boost to tank = 0.1 ug/L Mn.

To me the 0.1ug/L did not look right as seawater in 0.01ppm which is 10ug/L

Please correct me if i'm wrong but this is my calculation
Dissolve 1 gram in 1000 mL (grams) fresh water. Manganese = 280 ppm = 280,000ug/L

Take 1 mL (1 g) of that mix and dissolve in 1000 mL of fresh water. Mn = 0.28 ppm (=280 ug/L).
Therefore if my tank is 350L dosing 1ml would be 0.8ug/l so to get 10ug/L (0.01ppm) would require 13ml which I would dose in 1ml increments to be safe.

Doesn't appear there is a Manganese test kit around type in Manganese and you get Magnesium.

Thanks very much for your reply

bertoni · 03/08/2020, 10:25 PM

I agree that your solution is around 0.28 ppm. Dosing 1 ml per L would give you about 0.28 ppb, or 0.28 ug/L, so dosing 35 ml per L would be around 10 ppb. I think Randy's math seems correct, although the target dose is very small.

dodgy67 · 03/09/2020, 11:30 AM

Jonathon thanks for confirming, but I am still confused I have been following another thread https://www.*********.com/threads/di...n-help.477189/ where there is much debate on what solution to take the dose from

dodgy67 · 03/09/2020, 11:34 AM

*********.com/threads/diy-manganese-calculation-help.477189/

dodgy67 · 03/09/2020, 11:37 AM

it should be reef 2 reef

bertoni · 03/09/2020, 06:15 PM

I see the source of the confusion. Randy is concerned about overdosing, given the limits of detection of the measurement equipment.

If you want to dose around 10 ppb, I suggest making a 2.80 ppt solution. To make the 2.8 ppt = 2800 ppm, that's be about 10 grams of your product with enough water to make 1 L, and then 1 ml per L of tank water would add about 2.8 ppb. So it'd be about 350 ml to raise the tank to 2.8 ppb. I might try a small fraction of that, just out of general caution. Maybe someone can double-check my math.

If 10 grams won't dissolve in 1 L, we'll have to work from what does dissolve.

dodgy67 · 03/09/2020, 06:53 PM

Jonathan many thanks for your help with this, as you say there is lots of confusion on various sites so i'll make up a solution and take dosing steadily. Will let you know how it goes

Many thanks again

dodgy67 · 03/19/2020, 08:51 AM

Jonathan, from the original 1gm to 1 litre, I added 9 more to make up to 10 and dosed slowly over a couple of days 12ml. Several SPS did seem to stretch polyps out more, but a 50 headed Duncan closed up and my Goniapora went all droopy, left it a few more days then did a 15 Gall water change, and only today has the Duncan come out and the Goni looks better, so any dosing I do may be from the second dilution.

bertoni · 03/19/2020, 10:23 PM

Different corals often seem to respond differently to supplements. I am not sure why corals should have problems unless the manganese was actually higher than expected, or the supplement had some sort of problematic contamination. Hard to say.

03/07/2020, 10:24 AM	#1
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	Manganese dosing Read an article recently where Randy commented that Manganese is 28% by weight, I have just received a packet of Manganese (ll) Chloride Tetrahydrate 98% assume this is not 98% Manganese before I recalculate dosing. Thanks in advance for any advice. __________________ Dave 3 years still lots to learn about reefing Mag Curve 5 Skimmer, Jebao 4 way dosing pump,4 way slave, Maxspect Gyre 2 x XF230 T5 4x39w 2xBlue 1xBlue Plus 1xPurple Mixed SPS & LPS Current Tank Info: Red Sea Max C130. Self built 44x19x19 tank and stand June 2016 Maroon Clowns , 2 Pajamas, Sand sifting Goby, mixture of SPS and LPS

03/07/2020, 07:31 PM	#2
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Let's go through the math. Manganese chloride is MnCl₂. The molecular mass of the Cl part is 71.0. The Mn part is about 55. H₂O has a molecular mass of 18, and this is a tetra-hydrate, so the water part is 4 * 18 or 72. The mass per molecule is thus 198, of which 55 units are manganese, which leads to about 28% manganese by weight. To dose 1 ppm, which is about 1 mg/L, lets just say 4 mg/L of your manganese product, since 28% is close enough to 25%. What kind of scale or measuring equipment do you have on hand? __________________ Jonathan Bertoni Last edited by bertoni; 03/07/2020 at 10:03 PM.

03/08/2020, 04:40 AM	#3
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	This was the original thread I was following Following this recipe by @Randy Holmes-Farley Manganese(II) chloride tetrahydrate is 28% manganese by weight. Here's a recipe: Dissolve 1 gram in 100o mL (grams) fresh water. Manganese = 280 ppm. Take 1 mL (1 g) of that mix and dissolve in 1000 mL of fresh water. Mn = 0.28 ppm (=280 ug/L). Add 1 mL of that to 100 mL of fresh water. Mn = 2.8 ug/L Add 13.5 mL of that to 100 gallons of tank water. Conc boost to tank = 0.1 ug/L Mn. To me the 0.1ug/L did not look right as seawater in 0.01ppm which is 10ug/L Please correct me if i'm wrong but this is my calculation Dissolve 1 gram in 1000 mL (grams) fresh water. Manganese = 280 ppm = 280,000ug/L Take 1 mL (1 g) of that mix and dissolve in 1000 mL of fresh water. Mn = 0.28 ppm (=280 ug/L). Therefore if my tank is 350L dosing 1ml would be 0.8ug/l so to get 10ug/L (0.01ppm) would require 13ml which I would dose in 1ml increments to be safe. Doesn't appear there is a Manganese test kit around type in Manganese and you get Magnesium. Thanks very much for your reply __________________ Dave 3 years still lots to learn about reefing Mag Curve 5 Skimmer, Jebao 4 way dosing pump,4 way slave, Maxspect Gyre 2 x XF230 T5 4x39w 2xBlue 1xBlue Plus 1xPurple Mixed SPS & LPS Current Tank Info: Red Sea Max C130. Self built 44x19x19 tank and stand June 2016 Maroon Clowns , 2 Pajamas, Sand sifting Goby, mixture of SPS and LPS

03/08/2020, 10:25 PM	#4
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I agree that your solution is around 0.28 ppm. Dosing 1 ml per L would give you about 0.28 ppb, or 0.28 ug/L, so dosing 35 ml per L would be around 10 ppb. I think Randy's math seems correct, although the target dose is very small. __________________ Jonathan Bertoni

03/09/2020, 11:30 AM	#5
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	Jonathon thanks for confirming, but I am still confused I have been following another thread https://www.*********.com/threads/di...n-help.477189/ where there is much debate on what solution to take the dose from __________________ Dave 3 years still lots to learn about reefing Mag Curve 5 Skimmer, Jebao 4 way dosing pump,4 way slave, Maxspect Gyre 2 x XF230 T5 4x39w 2xBlue 1xBlue Plus 1xPurple Mixed SPS & LPS Current Tank Info: Red Sea Max C130. Self built 44x19x19 tank and stand June 2016 Maroon Clowns , 2 Pajamas, Sand sifting Goby, mixture of SPS and LPS

03/09/2020, 11:34 AM	#6
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	*********.com/threads/diy-manganese-calculation-help.477189/ __________________ Dave 3 years still lots to learn about reefing Mag Curve 5 Skimmer, Jebao 4 way dosing pump,4 way slave, Maxspect Gyre 2 x XF230 T5 4x39w 2xBlue 1xBlue Plus 1xPurple Mixed SPS & LPS Current Tank Info: Red Sea Max C130. Self built 44x19x19 tank and stand June 2016 Maroon Clowns , 2 Pajamas, Sand sifting Goby, mixture of SPS and LPS

03/09/2020, 11:37 AM	#7
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	it should be reef 2 reef

03/09/2020, 06:15 PM	#8
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I see the source of the confusion. Randy is concerned about overdosing, given the limits of detection of the measurement equipment. If you want to dose around 10 ppb, I suggest making a 2.80 ppt solution. To make the 2.8 ppt = 2800 ppm, that's be about 10 grams of your product with enough water to make 1 L, and then 1 ml per L of tank water would add about 2.8 ppb. So it'd be about 350 ml to raise the tank to 2.8 ppb. I might try a small fraction of that, just out of general caution. Maybe someone can double-check my math. If 10 grams won't dissolve in 1 L, we'll have to work from what does dissolve. __________________ Jonathan Bertoni

03/09/2020, 06:53 PM	#9
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	Jonathan many thanks for your help with this, as you say there is lots of confusion on various sites so i'll make up a solution and take dosing steadily. Will let you know how it goes Many thanks again __________________ Dave 3 years still lots to learn about reefing Mag Curve 5 Skimmer, Jebao 4 way dosing pump,4 way slave, Maxspect Gyre 2 x XF230 T5 4x39w 2xBlue 1xBlue Plus 1xPurple Mixed SPS & LPS Current Tank Info: Red Sea Max C130. Self built 44x19x19 tank and stand June 2016 Maroon Clowns , 2 Pajamas, Sand sifting Goby, mixture of SPS and LPS

03/19/2020, 08:51 AM	#10
dodgy67 Dave Join Date: Dec 2014 Location: Leighton Buzzard UK Posts: 122	Jonathan, from the original 1gm to 1 litre, I added 9 more to make up to 10 and dosed slowly over a couple of days 12ml. Several SPS did seem to stretch polyps out more, but a 50 headed Duncan closed up and my Goniapora went all droopy, left it a few more days then did a 15 Gall water change, and only today has the Duncan come out and the Goni looks better, so any dosing I do may be from the second dilution.

03/19/2020, 10:23 PM	#11
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Different corals often seem to respond differently to supplements. I am not sure why corals should have problems unless the manganese was actually higher than expected, or the supplement had some sort of problematic contamination. Hard to say. __________________ Jonathan Bertoni