Magnesium in tap water

dw1305

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Hi all,
Does it means that we can pour 50 ppm of N, 50 ppm of K, 50 ppm of Fe, 50 ppm of B, 50 ppm of Mn and plants will selectively choose whatever they need?
They don’t ever actually ever choose, it always depends on the concentration of ions in solution, and valency, that is the “taxi on the rank” analogy.

Plants might have mechanisms to protect them from iron toxicity etc. but the problem with most trace elements (Cu, Zn etc.) is that they are always in short supply, so “unnatural” amounts are often toxic.

My guess is that Liebig’s law of minimum is more important than ratios, but that they both are relevant to some degree.

Cheers Darrel
 
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I am also interested in this topic.
It seems like I need to add intolerable amounts of Mgso4 to my tank. Or else some plants will suffer and this might be the reason some other plants are stunted.
Not 100% sure about this yet, but trying out different solutions for this.
There are other sources for magnesium available.
Rotala butterfly calc. Lists magnesium gluconate, and on eBay there Are a lot of sellers offering magnesium glycinate.

Could one of these two be a better alternative for magnesium in a planted aquarium?
I am a total noob when it comes to chemistry and I have no idea what glycinate means...... Or does.
@dw1305
Is magnesium gluconate possibly harmful in Any way? By itself or combined with other chemicals we use in our tanks?
I just wiped out my livestock one week after switching to magnesium gluconate and wonder if it was this switch is to blame....
 

jolt100

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Was this an analytical grade of Magnesium gluconate or a commercial "food supplement". These appear to have other Additives which could be harmful.
Magnesium sulphate (Epsom salts) is cheap and doesn't affect your livestock.
Cheers
John
 

dw1305

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Hi all,
I just wiped out my livestock one week after switching to magnesium gluconate and wonder if it was this switch is to blame..
@dw1305 Is magnesium gluconate possibly harmful in Any way?
Sorry to hear that. I'm not sure, but I wouldn't have thought there would be any problem as it is a small addition of organic matter (gluconate is C6H12O7), and would be similar to adding citric acid.
These appear to have other Additives which could be harmful. Magnesium sulphate (Epsom salts) is cheap and doesn't affect your livestock
I've only ever added "Epsom Salts" as a magnesium source.

cheers Darrel
 

Oldguy

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My tap water is about 100pm hardness. I assume that it is mainly from calcium salts. (only small dolomitic inclusions in the local geology) I cut this approx 50:50 with rain water and add Epson Salts to give about 15ppm Mg in the water used for approx 50% weekly water change. (Also add to this water potassium sulphate to yield approx 10ppm.)

Ca to Mg ratio is about 3 to 1. This is by chance and not design. I want to run a soft water tank but with magnesium for plant growth. Mg is often overlooked as it is assumed to be in tap water, it may not be. Why use rain water, well its free and I have to find a use for it;).

People have beautiful planted tanks with hard water, but they may be adding more CO2 and different chelates than myself. Each to their own.
 
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Was this an analytical grade of Magnesium gluconate or a commercial "food supplement". These appear to have other Additives which could be harmful.
Magnesium sulphate (Epsom salts) is cheap and doesn't affect your livestock.
Cheers
John
It was supposedly 100% pure but I bought it from a seller who also sells a lot of nutritional supplements so who knows.

I don't know who the perp is, but I have a few "suspects".
I add 1 gram of k2co3 to the 100l of new water. This might have caused some wild pH swing or depleted the oxygen levels in combination the co2 in this new tap water and the pressurised co2 added thru my reactor.
It happened the night after water change sunday.
I have seen a bit cloudy gray haze in the water the day after w.c before, but it has passed.
My tap water is so soft that I need to add something to raise the kh or else the pH in the tank falls to under 6.
I have measured 5.8 and that seems a little low.
I will change kh source from k2co3 to khco3 and have another look my routine for mixing up and adding water to the tank.

I asked my water supplier for a report on what it contains and got a very detailed description for just about anything you think of. Except calcium and magnesium. It listed a bunch of pesticides and even bacteria numbers but not the two elements I was really interested in.
So I am just going to assume the little gh in the water is all calcium and no magnesium.
When "reconstitution" the new water, I have targeted Mg levels from 5ppm and up to 16ppm with mgso4.
I have not been able to draw any conclusion by reading the plants response to these changes. And i have no way of measuring in Mg in water , so I can not say how much ppm (if any)Mg falls in a week.
How much Mg can a high tech tank with high plant volume of mostly fast growers consume in 7 days???

And while I am trying to figure out Mg, something is stunting my A.R pink and making it shrivel and curl. Maybe it is Mg. Maybe it is micro related.
 

Oldguy

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Except calcium and magnesium
I requested Mg in ppm from my water company and got a reply in degrees Clark of CaCO3 equivalent. Very useful I don't think. As my posting above I assumed nil and added Epson salts to about 15pmm Mg.

Depending on how serious you are to find the amount of Mg in your tap water and as an extension the deletion rate in your tank there are 'wet' methods of analysis given in detail on line, but you will need a burette and pipette and other odds and sods of lab equipment. Do an internet search for Ca and Mg with EDTA and Eriochrome Black. It looks complicated but it depends on your back ground. In the UK it would be about 'A' level chemistry and first term, first year undergraduate 'catch up' level.

The real killer is access to equipment and reagents, but with eBay, not that expensive to buy. Oh and the end point needs a bit of practice.

Deletion rates would be interesting but difficult to generalize. EI assumes an excess and plants take what they need.

Good luck.
 

Witcher

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something is stunting my A.R pink and making it shrivel and curl. Maybe it is Mg. Maybe it is micro related.
I can bet it's not enough Ca with relation to Mg and K. My A.R. mini was always burning its tips when I was playing with water hardness (using different Ca/Mg ratios) and amount of K - it happened usually at too low level of Ca.
 
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Hi all, Sorry to hear that. I'm not sure, but I wouldn't have thought there would be any problem as it is a small addition of organic matter (gluconate is C6H12O7), and would be similar to adding citric acid. I've only ever added "Epsom Salts" as a magnesium source.

cheers Darrel
This is from Wikipedia :
In aqueous solution at neutral pH, gluconic acid forms the gluconate ion. The salts of gluconic acid are known as "gluconates". Gluconic acid, gluconate salts, and gluconate esters occur widely in nature because such species arise from the oxidation of glucose

Glucose is fruit sugar right?
Could adding 10grams of Mg gluconate in 160 liters of water possibly cause a bacteria bloom or other issues?
I am experiencing melting and stem rot on hygrophila compact and A.r pink despite a couple of extra water changes this week.

Another possible cause is the Miller's microplex I have been using for 2 weeks.
I have only Dosed this very sparingly and just twise a week to get a little extra Manganese. This had a positive effect at first so I really hope it is not to blame for the mess in my tank. I am aware that it contains ridiculous amounts of copper.
 

Simon Cole

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25 Dec 2018
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Buckingham
Seachem Flourish Iron is a ferrous gluconate fertlizer. It works for me and many others without causing algae. The actual quantities are so small I doubt you'll have a bloom, but yes I'd put sugars as a major point of conjecture in terms of algal blooms.
 

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