Magnesium in GH Booster and dry dosing. Why the vast difference?

Zak Rafik

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Hi Guys

I'm now dosing EI salts to my 300lts/ 80 gal planted tank by using the on-line calculator at https://www.thenutrientcompany.com/aquarium/calculators/ei_calculator/.

It say to dose 2 teaspoons of Magnesium Sulphate (MgSO4) for 3 times a week.
That's a total of 6 teaspoons per week.

Now I have seen at the Barr Report
http://www.barrreport.com/forum/bar...ndex/2938-ei-light-for-those-less-techy-folks

There is no mention of Magnesium Sulphate dosing separately.
Instead Magnesium Sulphate is dosed as part of GH booster.
GH Booster is composed of :
1 part magnesium sulfate,
3 parts potassium sulfate and
3 parts calcium sulfate.

In the Barr Report website it mentions to dose
+/- 1 teaspoon once a week (water change only) for 60 to 80 gal tank.
So according to Tom Barr website, magnesium is dosed one seventh part of a teaspoon.
That's several times less. ( maybe some one will be kind enough to do the maths for the exact percentage)

Now, I ask why the vast difference between 6 teaspoons a week and less than 1/7th of a teaspoon a week?
Is there a calculation error?


BTW. My tape water ph is 6.8

Thank you very much.
 

dw1305

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Hi all,
I think it is probably to do with differences in geology and tap water between the UK and USA.

It doesn't really matter if you add "luxury" magnesium, there isn't any down side to raised Mg levels.

Have a look at the <"Magnesium supplement.."> thread for some more geological detail, but the basic premise is that if a limestone (like the chalk that underlies S. Britain, N. France etc) formed in an ocean basin it will be relatively low in magnesium, but if the limestone formed in a shallow sea (that subsequently evaporated) it will be much more magnesium rich, having undergone dolomotization. Tectonic activity can also lead to hydrothermal magnesium deposition

The Mediterranean basin has dried out at times, and undergone extensive tectonic movement and you get the Italian Dolomite mountains etc.

cheers Darrel
 

Zak Rafik

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With all due respect, I'm getting tired of "oh it doesn't matter if your over dose".
I'm sure this type of over dosing must have some impact on other issues.
This is the only forum where all the issues in a tank is always due to insufficient Co2 and not enough flow.
 

Andy Thurston

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This is the only forum where all the issues in a tank is always due to insufficient Co2 and not enough flow.
Thats because most people with high techs on here dose EI so when they have suffering plants it can only be light, co2 and/or flow.

EI is a good starting point and once you get your co2 right you can reduce dosing if you want but be aware that you could end up with problems again.

The nutrient company calculator is quite high dosing even for EI and it you look at the APFUK EI recipe its much less.
With all due respect, I'm getting tired of "oh it doesn't matter if your over dose".

If you don't like the answers you get why bother asking the questions in the first place

If you don't like high levels of nutrients in your tank you can always go low tech, quite a few members have and have had beautiful results. Darrels duckweed index will help you to minimise nutrients in your water
 

xim

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Let's get some facts straight in the context of EI.

What level does Tom suggest?

"I generally suggest adding GH booster to raise the GH about 1-2 degrees from what ever it might be in the tap."
http://www.barrreport.com/forum/bar...-for-those-less-techy-folks?p=35853#post35853

Now, does 1 Tsp raise enough GH for you 300 litre tank?
Have a look at this: "One Tablespoon or 16 grams will raise the GH of 20 gallons of water by 3 degrees or 1 meg/liter"
http://www.aquariumfertilizer.com/i...rnEdit=2&Returnitemname=&ReturnShowItemStart=

1 Tbs equals 3 Tsps...
So 3 Tsps will raise GH of 60 gallons of water by just 1 degree. Let alone your 80 gallons with 1 Tsp.

Actually, if anything, your tank should fall into the the "80-100 Gallon Aquariums" section which doesn't exist in the guide.
I think adding 6 TSPs is about right in EI's book, this will add 10 PPM of Mg for your tank.

Then you may wonder how much Mg is enough?
http://www.barrreport.com/forum/bar...7-how-much-magnesium-can-plants-use-in-a-week

:rolleyes:
 
Last edited:

xim

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So 1 tsp of GH Booster can't boost the GH of your 80 US gallon tank by 1 degree.

If 16 grams (3 tsps) of GH Booster raises the GH of 60 US gallons of water by 1 degree.
Then for a 80 US gallons (your tank size), that would be 21.3 grams.

By the ratio, 21.3 grams of GH Booster contains 3.04 grams of Epsom salt.
This adds 1 PPM of Mg to 300 litres of water.

The conversation linked in the previous post suggests adding 3.5 PPM of Mg weekly is enough.
It didn't reveal what the minimum level is. So is adding 1 PPM of Mg a week OK?

Now, look at this newer thread I've just stumbled on:
"So the take home is not to worry about accuracy with the Mg, just add a little bit, just enough to prevent the chance of limitation.
So dose say 2 ppm a week, if you do EI, then 50% weekly water change, this will only ever add no more than 4 ppm extra."
http://www.barrreport.com/forum/bar...ing-calcium-and-magnesium?p=167479#post167479

Hmmm, now the TNC's recommended amount seems excessive.

PS: IME, I couldn't grow Heteranthera Zosterifolia until I added 3.5 PPM of Mg a week.
But I have not tried 2 PPM a week and it could be something else, though.
 
Last edited:

Zak Rafik

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Hi
300 litres don't convert to 80 gallons!
Is 65UK gallons!
hoggie
Hi Hogan :)
Ok may be I should have been more detailed. The vol I stated was 80 US gallons and UK gallons.
I guess I'll have to more careful on the units of measurement.
Cheers.
 

hogan53

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Hi all,
I think it is probably to do with differences in geology and tap water between the UK and USA.
It doesn't really matter if you add "luxury" magnesium, there isn't any down side to raised Mg levels.

As Darrell stated Zak....Tom Barr's Tap water is probably full of Magnesium....so doesn't need as much!
Plus every aquarium is unique and the dosing regime does not to be set in stone!
Cheers
hoggie
 

Zak Rafik

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So 1 tsp of GH Booster can't boost the GH of your 80 US gallon tank by 1 degree.

If 16 grams (3 tsps) of GH Booster raises the GH of 60 US gallons of water by 1 degree.
Then for a 80 US gallons (your tank size), that would be 21.3 grams.

By the ratio, 21.3 grams of GH Booster contains 3.04 grams of Epsom salt.
This adds 1 PPM of Mg to 300 litres of water.

The conversation linked in the previous post suggests adding 3.5 PPM of Mg weekly is enough.
It didn't reveal what the minimum level is. So is adding 1 PPM of Mg a week OK?

Now, look at this newer thread I've just stumbled on:
"So the take home is not to worry about accuracy with the Mg, just add a little bit, just enough to prevent the chance of limitation.
So dose say 2 ppm a week, if you do EI, then 50% weekly water change, this will only ever add no more than 4 ppm extra."
http://www.barrreport.com/forum/bar...ing-calcium-and-magnesium?p=167479#post167479

Hmmm, now the TNC's recommended amount seems excessive.

PS: IME, I couldn't grow Heteranthera Zosterifolia until I added 3.5 PPM of Mg a week.
But I have not tried 2 PPM a week and it could be something else, though.

Hi Xim, :)

Thanks for shedding some light on this issue.
Ok, Would you say I go with option 1 or 2?

Option.1
Dose GH booster for my 300ltr / 80US gal.
If so, how much to dose in order to have a Magnesium 3.5ppm weekly. Is it 74.55 grammes?
That seems allot, especially potassium (K). Correct if I'm wrong. Thanks.

Option.2
Just dose 10 grammes of Magnesium Sulfate to get 3.5ppm weekly ( from APC on-line calculator)

The main reason I'm confused on this EI dosing is due to my plants melting away at the bottom. Please see the video which I took today. The plants seem to grow and after 4 or 5 day, it melts. This happen to my other types of plants as well.
This growing and sudden melting has been happening for the past 8 months.
I can't figure out what that missing part is that is causing this.

I know for sure my Co2 is high. All my 20+ dead fish and 80+ shrimps can vouch for that :(
My DC is lime green after 4 hours of lights on.

I'm now dosing as per APC on-line calculator the following:
20 ppm of KNO3 weekly
3ppm for PO4 weekly
0.7ppm for Fe (CSM+B & Fe combined) weekly

As for Magnesium I was doing 6 teaspoons (10ppm) weekly.

 

dw1305

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Hi all,
It doesn't really matter if you add "luxury" magnesium, there isn't any down side to raised Mg levels.
I aim for fairly low levels of all nutrients, because I'm low tech, I don't grow any demanding plants and I keep soft-water fish.
With all due respect, I'm getting tired of "oh it doesn't matter if your over dose". I'm sure this type of over dosing must have some impact on other issues.
I agree with you, but the reason why it doesn't matter if you add more magnesium is because magnesium naturally occurs at high levels in a lot of soils and water.

You can think of it in a similar way to calcium, we don't really measure divalent ion (usually calcium, but including magnesium) levels in ppm, we use dGH "degrees German Hardness" and categorize the water as "soft", "hard" etc. this is because the actual value is relatively irrelevant, once you reach a certain threshold value.

Once you raise dKH above about 4dKH the extra dGH you add doesn't really have much effect. If you want to spawn "black water" fish you need a low dGH, and some plants (Tonina) won't grow at elevated calcium levels.

I don't know about magnesium in the context of aquatic plant growth, but on the <"Lizard peninsula in the UK"> you have serpentine derived ultra basic soils, which are rich in magnesium, but low in calcium, and you get calcicole and calcifuge plants in the same community.

cheers Darrel
 

Zak Rafik

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Hi all, I aim for fairly low levels of all nutrients, because I'm low tech, I don't grow any demanding plants and I keep soft-water fish. I agree with you, but the reason why it doesn't matter if you add more magnesium is because magnesium naturally occurs at high levels in a lot of soils and water.

You can think of it in a similar way to calcium, we don't really measure divalent ion (usually calcium, but including magnesium) levels in ppm, we use dGH "degrees German Hardness" and categorize the water as "soft", "hard" etc. this is because the actual value is relatively irrelevant, once you reach a certain threshold value.

Once you raise dKH above about 4dKH the extra dGH you add doesn't really have much effect. If you want to spawn "black water" fish you need a low dGH, and some plants (Tonina) won't grow at elevated calcium levels.

I don't know about magnesium in the context of aquatic plant growth, but on the <"Lizard peninsula in the UK"> you have serpentine derived ultra basic soils, which are rich in magnesium, but low in calcium, and you get calcicole and calcifuge plants in the same community.

cheers Darrel

Hi Darrel
Pardon me if I had sounded rude. But desperation to solve my long term problem of plants growing and then suddenly melting, is driving me up the wall.
I value your effort in answering my questions.
Cheers
 

ltsai

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Zak, totally understand your fustrations. I ended up with growing emmerse plants instead of a planted tank, but not successful in growing them too.
 

xim

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I would choose option 2. GH Booster is very confusing about its composition.
Tom Barr said one thing, the manufacturer said another. :crazy:

Melting at the bottom within just 3-4 day period is extremely fast. And you havn't planted them too
close together to cause suffocating. So I think it's probably from toxicity or damage.

Do you use liquid carbon or H2O2? Or may be rough handling? I never keep the plant in the video
but their stems look big and kind of stiff. May be the flow is too strong for them there?

I used to have Rotala green and Java fern melt suddenly. I spent a long time trying different dosings
to no avail.

Then I noticed the melting areas were the first parts that the flow hit. So I suspected it might be from
topping up water. I compared all the parameters I could (pH, NH3/4, temperature, Chlorine) between
tank water and the topping up water but found nothing wrong. So I tried pouring it very slowly into the
outflow opening area for the best mixing with the tank water before hitting the plants and the issue
almost went away. I mean the areas still suffer a bit but no more melting.

It's strange that I'm not that gentle when I refill the tank during water change (to save time),
but there is no problem even though the amount of new water is huge. It happens only with
the topping up water.
 

xim

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I would choose option 2. GH Booster is very confusing about its composition.
Tom Barr said one thing, the manufacturer said another. :crazy:

To clarify, I meant Tom said 2:1:1 but Greg said 3:3:1.
Yep, it's not written in stone. But the contradiction could frustrate newcomers.
 

dw1305

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Hi all,
ust dose 10 grammes of Magnesium Sulfate to get 3.5ppm weekly
That is going to be plenty. If you have really hard water, with large amounts of calcium, you get problems with the uptake of iron (Fe) and magnesium (Mg). Whatever formula your magnesium sulphate has on the container, when you use it will be "Epsom Salts" (MgSO4.7H2O) by the time you use it. This makes a difference to the magnesium content <"From your Help with EI calcs.... thread">.
The main reason I'm confused on this EI dosing is due to my plants melting away at the bottom. Please see the video which I took today. The plants seem to grow and after 4 or 5 day, it melts. This happen to my other types of plants as well. This growing and sudden melting has been happening for the past 8 months.
I think the problem with all your plants is because they've been grown emersed, which is why the old stems are rotting. Really high CO2 levels might convince the plant that it is still emersed, but in most cases it is going to go backwards before growing again.

I'd replant the small shoots and then just wait. If I was going to add new plants from a commercial source, I'd float them for a while before planting.

cheers Darrel
 

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