How much magnesium sulfate if Mg is 0 in tab water

LiamLiffey

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Jul 3, 2008
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Hi folks,
i have 0 Mg in my tab water and so i need to do sth. I bought magnesium sulfate (MgSO4x7H2O) but now i am not sure how much and how often i should use it. I am currently using esimative index program and a micro fertiliser wich adds a little MgO but like most not that much.

Thanks for any help.

Axel
 

Tom Barr

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You can add about 5ppm of Mg once a week or there about.
That should be enough to supply the plant need.

To figure out how much that is from MgSO4 (epsom salt), simply use a dosing calculator for the aquarium volume you have to get how many grams or mls of salt is needed to raise Mg to 5ppm.

I'd suggest adding the MgSO4 to the trace element mixture at this rate, so you dose say 1-2ppm Mg to the aquarium each time assuming 3x a week dosing.

Regards,
Tom Barr
 

LiamLiffey

Junior Poster
Jul 3, 2008
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Hamburg, Germany
Hi,
I just got the new data from my water network. Here it is.
Calcium: 40mg/l
Magnesium: 3mg/l
Sodium: 8mg/l
Potassium: 1mg/l
Fe: 0,01mg/l
Manganese: 0
Ammonium: 0

GH: 6,2
KH: 5,8

Can you please check this and tell me if you see sth. else to do then raising Mg up to about max 10mg/l? The question is if a GH booster will be needed or helpful.
Thanks a lot!

Axel

P.s. Is there a ratio for Magnesium, Calcium and Potassium or an ideal amount of each?
 

VaughnH

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If my water report looked like that I would think I had soft water, a bit light on GH, and needing some more magnesium. I would dose Equilibrium per the bottle directions to raise the GH by 2 dGH.
 

Hrafnkell

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Jan 9, 2008
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Just for comparison, here are the same water parameters in Reykjavik, Iceland.

Calcium (Ca): 5 mg/L
Magnesium (Mg) : 1 mg/L
Sodium (Na): 10 mg/L
Potassium (K): 0.6 mg/L
Iron(Fe):
 

VaughnH

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Equilibrium contains magnesium, so if I were trying to raise the GH I would just use Equilibrium. I actually dose a little magnesium - epsom salts - mixed in with my trace element mix, routinely, just to be sure I do have some magnesium. My water report says the range of concentrations of magnesium in my tap water varies widely, with the low value too low. Since I never know when the water has that low value I just dose some magnesium all the time.
 

Tom Barr

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LiamLiffey;26777 said:
Hi,
what happens if i dose too much Mg? Algae problems?

No, there's never been any association there.
Stunted plants perhaps if you go above the 50-60ppm ranges.
Davis tap water has an average(this does not imply it's always this high or low, all tap waters vary somewhat, they report averages) of 52mg/l or ppm.

I had a few issues, but not many.
It was due to the high KH more than the GH or Mg.

When the KH was removed and the Gh added back, there was no such issue.

You can add Equilibrium if you wish, it cost a fair amount. GH booster is sold here and I think Tobi in (Flowgrow forums) Germany might have someone that has it, I know Aqua essentials in the UK has it and sells it.

Otherwise, I'd just add 5ppm of Mg once a week etc or spread the 5 ppm out over 3x a week or 7x a week daily type dosing.

Not to critical as long asd there is enough MG.
It's unlikely that your tank would use more than 5ppm of Mg per week.

I'd assume no Mg in the tap water given the low 3ppm number.

Regards,
Tom Barr
 
P

paludarium

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LiamLiffey;26777 said:
Hi,
what happens if i dose too much Mg? Algae problems?
Hi,

Three weeks ago I did a serious mistake by pouring too much MgSO4 into my natural platned tank. Actually I intended to add Al2(SO4)3, but as I saw pH remained stable, I added more and more..... I don't know the exact amount that I poured in into the tank. In the following days, many stem plants stunted, including Ludwigia repens 'rubin', Limnophila aquatica, and Proserpinaca palustris. I decided to wait and see, then Ludwigia repens showed chlorosis symptoms. Eventually tetras like rummy nose and cardinal tetra were killed and I had to do an 80% water change one week after pouring MgSO4. The plants regained their growth after water change, except Ludwigia repens 'rubin' which remains its clorosis status and stunt. However, I did not have any algae issue.

Regards,
Erich