Dosing Manganese(II) chloride tetrahydrate

[JBNY]

Can we talk about Manganese dosing and creating a solution that we can dose in our aquariums long term?

A number of people keeping SPS have been experimenting with dosing Manganese in our tanks. I have been mixing Manganese Chloride and dosing that for almost 5 months, at this point I am dosing 0.0008 mg/l daily. I have still yet to find Mn in any ICP tests that I have done, so I am beginning to think that the manganese that I am using, Manganese(II) chloride tetrahydrate, is not as effective as it could be. Randy, you had mention that when mixing it with fresh water the solution will be sensitive to O2 (which can cause oxidation and subsequent precipitation of MnO2), so it should be keept tightly closed.

So my question is there a way I can chelate the Manganese so that is will stay in solution till I need it? Preferably I would like to make a solution that I can put in a dosing container for a month or more and dose automatically daily.

I had tried to use sodium citrate to mix with the Manganese. I made a 100ml 0.5 Mole Mn stock solution that I was transferring 6ml to 1L to make a dosing solution, but I kept getting crystals in the stock manganese solution after about 6 hours, by 24 hours there was a significant amount of crystallization in the jar.

So what else can I try?

 

[Randy Holmes-Farley]

I actually do not know if chelated manganese is any more (or less) resistant to oxidation than is unchelated manganese.

How much are you dosing relative to the limit of detection of the ICP?

 

[JBNY]

I am dosing 0.0006 mg/l daily. How long do you think I can have just the Manganese Chloride out in a doser before I need to be concerned about oxidation?

 

[Randy Holmes-Farley]

I am dosing 0.0006 mg/l daily. How long do you think I can have just the Manganese Chloride out in a doser before I need to be concerned about oxidation?

I really have no idea. Sorry.

 

[JBNY]

Ok. No worries Randy. I will ask around and see if I can find some info

 

[Big E]

I have been mixing Manganese Chloride and dosing that for almost 5 months, at this point I am dosing 0.0008 mg/l daily. I have still yet to find Mn in any ICP tests that I have done,

Have you thought about getting another source to test manganese? I'm not convinced Triton is accurate as it has proven to be way off in some unbiased results. The same with zinc, and these are the two trace elements people are experimenting with.

I saw this company mentioned by bertoni...............I don't know anything about them nor am I recommending them, but a second source might be helpful to make sure of what is going on.

http://enclabs.com/index.html

 

[Robthorn]

I have been dosing reefgrow manganese for somewhere between 6 and 8 months. I never really keep track. I too would like to add it to a doser since I only add about 2ml of their recommended mixing a week and would like to be more consistent.

I do not know anything about oxidizing but I am asssuming it leaves what we are dosing ineffective?

Justin Leone is the owner of Reefgrow and while very busy gets pretty geeky talking science so you might try to shoot him a message and see what he has to say. Not sure he would give you a diy formula but he can direct you where to buy a small package to test for yourself. Or the website may even list exactly whats in the package.

 

[JBNY]

So what I have been doing for the last 6 months or so it mixing up enough to last about a month. The thought being that it will not oxidize so fast as to be useless in a month so that is how I have been doing it. I have it on a doser and just mix up a new solution once a month, takes me about 5 minutes.

 

[Robthorn]

Sp once it oxidizes it becomes bound up and unusable?

 

[Randy Holmes-Farley]

I do not know that it becomes any less effective, just different. But the primary form in the ocean is Mn++.

 

[Randy Holmes-Farley]

Here's a discussion with respect to drinking water. Note especially the last sentence.

Manganese (Mn) is a transition metal which can exist in a range of oxidation states, +2, +3, +4, +6 and +7. The divalent form, Mn(II), predominates in most waters at pH 4-7. If the pH and redox potential of the water are increased (by the addition of lime and chlorine) then Mn(II) may be oxidised to Mn(IV). The complex series of oxidation and adsorption reactions which occur in aerobic water, means that manganese dioxide (MnO2) is eventually formed. At times MnO2 may be present as a colloid, which essentially behaves as a solution in terms of transport. MnO2 is essentially a biologically unavailable, insoluble form of manganese.

http://dwi.defra.gov.uk/research/completed-research/reports/DWI70-2-276.pdf

 

[Robthorn]

Thank you for the info Randy.

I have had mine mixed for many months 4 to 8 maybe without any crystal formation that I can see at least.

 

[Randy Holmes-Farley]

Thank you for the info Randy.

I have had mine mixed for many months 4 to 8 maybe without any crystal formation that I can see at least.

Has it turned brown?

 

[Robthorn]

No sir it is still pretty clear. It comes as a small liquid pack you mix with ro/di water to make 2 liters. I do not know what concentration is desired or how potent the pack actually is.
I can't say I have actually studied it but I shake the jug up pretty good and then pull 2 ml out with a transparent syringe. It looks clearish and I see no particles floating. The jug is actually black but I would assume my crazy shaking would knock something loose. Clearish means it is not perfectly clear but I do not think the slight tint it may have had the first day I mixed it has changed at all.

 

[Randy Holmes-Farley]

Oh, it's a commercial supplement? It might have antioxidants in it.

 

[Robthorn]

It is a Reefgrow brand element.

 

[Randy Holmes-Farley]

That product says it has organics in it, They may be chelating the manganese and holding it in solution.

 

[Robthorn]

Yeah Randy you know I don't pretend to understand that stuff. I can build just about anything though. Lol

 

[Jason mack]

My lFS told me too raise my magnesium too 1700 mg/l to kill off gha .. I used magnesium plus from Colombo ,it worked very well .. my question is .. is this in any way detrimental too fish or corals with mag so high .. what, if any are the pros and cons .. is this a good method against gha ??

 

[Randy Holmes-Farley]

My lFS told me too raise my magnesium too 1700 mg/l to kill off gha .. I used magnesium plus from Colombo ,it worked very well .. my question is .. is this in any way detrimental too fish or corals with mag so high .. what, if any are the pros and cons .. is this a good method against gha ??

FWIW, this is a thread about manganese, not magnesium, but to answer your question, most folks do not find that elevated magnesium kills their hair algae. If you use certain brands, some folks find bryopsis (a specific species of problem aglae) dies, but that might be a toxin in the magnesium supplement rather than the magnesium itself.

Tat all said, if you want to boost magnesium to 1700 ppm as an experiment, it should hurt most creatures. Snails can become lethargic at high levels, but they usually recover.