Dosing General Hardness

JadeButterfly

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Jan 23, 2005
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Re: Dosing General Hardness

I actually have the same question as Ian. How do I know if my tank is deficient in Ca or Mg.? Like, how will I be able to tell from my plant's growth?

In Toronto here, I have very hard water. ~200ppm

I haven't looked at the water report (not even sure how to...) to see how much Mg and Ca is in the water...
 

JadeButterfly

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Jan 23, 2005
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Re: Dosing General Hardness

okay just checked.

I only have access to the 2003 annual report

Average Ca - 34ppm
Average Mg - 8.3ppm

how does those sound?
 

m lemay

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Jan 23, 2005
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Re: Dosing General Hardness

Those are both a little on the low side, not hard by any stretch. Should be adequate for growing plants. A little more calcium wouldn't hurt. Have you tested the gh out of your tap?
 

JadeButterfly

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Jan 23, 2005
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Re: Dosing General Hardness

yeah 200ppm, but what are the deficiency seen on plants when Ca and Mg is low? My plants all have been doing generally good...
 

chubasco

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Jan 24, 2005
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Re: Dosing General Hardness

What are you feeding your fish? When you test your tankwater, is there in
increase in GH, KH, from what's on tap? I know you're growing glosso, perhaps
your other plants are able to grow with these water parameters.

Bill
 

JadeButterfly

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Jan 23, 2005
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Re: Dosing General Hardness

actually my bad.
200ppm i think is from my tank

220ppm from tap for GH

I think my KH gets lowered from 140 to 120ppm because of CO2...

this is from what I recall, I haven't test my tap water in almost 3 weeks
the last time I test my tank water...(a week ago)... GH 200ppm, KH 120ppm
 

chubasco

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Jan 24, 2005
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Re: Dosing General Hardness

Scrolling back up to your annual water report of 2003, your water certainly
increased in hardness, didn't it? 200ppm GH and 120ppm KH, you are just
fine not adding anything (if Ca to Mg is 3-4:1). You can save the baking soda,
too. :)

Bill
 

Gill Man

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Feb 10, 2005
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Re: Dosing General Hardness

alexperez said:
Gill Man,

I quote "Since my first posting, I started using my new La Motte CaCO3 test. With this value and dGH and formulae, I can calculate Ca and Mg concentrations."

Could you tell me how you did that?
I have the La Motte Hardness(4824-DR-LT) and the La Motte Alkalinity (4491-DR) are these the same test kits you have?

Thanks!

Alex, I used Calcium hardness test, LM-3609. So here are the formulae I got from another forum(s), don't know which:

There are two different ways Ca is measured by test kits.

1. If the Ca from test kit is just for Ca, then
Mg = (dGH*17.1 - Ca*2.5)/4.1 (ppm)

2. If the Ca is for equivalent CaCO3,
Actual Ca = CaCO3/2.5
Mg = (dGH*17.1 - CaC03)/4.1 (ppm)


I can't verify the formulae, but it looks good to me. Don't know where the 4.1 comes from.
 

Roman

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Re: Dosing General Hardness

GreenStuff said:
Jade, You can find the symptoms of nutrient deficiencies on Chuck's site.

http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm

Problem is that they mostly look very similar. I mean you can tell if they are on new or old growth but that's it for me, since I don't have enough experience on the subject of nutrient deficiency. I don't think I want to have a lot of personal experience with that ;) , but then again I would like to know what's going on when there is a problem.

I have some problems in form of nutrient deficiency and I found almost exactly the same pictures of the same plant from somebody else. It looks so similar I could just say this is it. But he managed to cure the problem with adding calcium and I'm almost sure it's not calcium in my case. I didn't rule it out completely, but it will be the last thing to add calcium if everything else fails.
 

Roman

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Re: Dosing General Hardness

Gill Man said:
Alex, I used Calcium hardness test, LM-3609. So here are the formulae I got from another forum(s), don't know which:

There are two different ways Ca is measured by test kits.

1. If the Ca from test kit is just for Ca, then
Mg = (dGH*17.1 - Ca*2.5)/4.1 (ppm)

2. If the Ca is for equivalent CaCO3,
Actual Ca = CaCO3/2.5
Mg = (dGH*17.1 - CaC03)/4.1 (ppm)


I can't verify the formulae, but it looks good to me. Don't know where the 4.1 comes from.


This sure look nice, but is there any scientific explanation of this? How it works?
 

chubasco

Guru Class Expert
Jan 24, 2005
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Re: Dosing General Hardness

Gill Man said:
Alex, I used Calcium hardness test, LM-3609. So here are the formulae I got from another forum(s), don't know which:

There are two different ways Ca is measured by test kits.

1. If the Ca from test kit is just for Ca, then
Mg = (dGH*17.1 - Ca*2.5)/4.1 (ppm)

2. If the Ca is for equivalent CaCO3,
Actual Ca = CaCO3/2.5
Mg = (dGH*17.1 - CaC03)/4.1 (ppm)


I can't verify the formulae, but it looks good to me. Don't know where the 4.1 comes from.

I want to get a test kit for calcium, too, and thought the easiest way to
factor Mg is test for GH (with perhaps not really accurate AP Kit) test for
Calcium, then subtract that from GH for Mg. Would this be way off or what?
AP kit for GH measures in dGH so I would have to multiply by 17.9 for ppm.

Bill
 

JadeButterfly

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Jan 23, 2005
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Re: Dosing General Hardness

are there any commercial product I can dose to not only increase Ca and Mg, but to get them to a ratio of 3-4:1?

I don't have the dry ingredients on me and not sure of the exact amount of each I have in my water.

I think I do notice deficiency...my ludwiga...new leaves are nice,thick and shiny...but they are also kinda curled up, especially at the tips and edges.
 

Roman

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Re: Dosing General Hardness

bill ruyle said:
I want to get a test kit for calcium, too, and thought the easiest way to
factor Mg is test for GH (with perhaps not really accurate AP Kit) test for
Calcium, then subtract that from GH for Mg. Would this be way off or what?
AP kit for GH measures in dGH so I would have to multiply by 17.9 for ppm.

Bill

It's not only Ca++ and Mg++ that makes GH, there are some other things, so you can't just subtract Ca++ from GH to get Mg++. I wish it would be so simple :)
 

chubasco

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Jan 24, 2005
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Re: Dosing General Hardness

Roman said:
It's not only Ca++ and Mg++ that makes GH, there are some other things, so you can't just subtract Ca++ from GH to get Mg++. I wish it would be so simple :)

Me too! Was hoping for at least a ballpark figure :)

Bill
 

Ian H

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Jan 24, 2005
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Re: Dosing General Hardness

it is simple if you don't overcomplicate it. :) If you subtract the Ca++ tested value from the Gh value you will get a Mg figure close enough for your needs. Ca and Mg are the predominant substances that effect the Gh reading.

Ian
 

chubasco

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Jan 24, 2005
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Re: Dosing General Hardness

Ian H said:
it is simple if you don't overcomplicate it. :) If you subtract the Ca++ tested value from the Gh value you will get a Mg figure close enough for your needs. Ca and Mg are the predominant substances that effect the Gh reading.

Ian

Which is what I was asking in my post, thanks Ian!

Bill
 

Tom Barr

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Jan 23, 2005
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Re: Dosing General Hardness

It's highly unlikely, although remotely possible, you have any GH issue with a hardness of 200ppm. If you did have any issue, adding a small amount of MgSO4 would take care of it.

Regards,
Tom Barr
 

Roman

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Re: Dosing General Hardness

Ian H said:
it is simple if you don't overcomplicate it. :) If you subtract the Ca++ tested value from the Gh value you will get a Mg figure close enough for your needs. Ca and Mg are the predominant substances that effect the Gh reading.

Ian


How do you subtract the Ca++ tested value from the dGh value?

I did a test on bottled water with known characteristical ingredients for 1 liter:
Ca++ = 64,5 mg
Mg++ = 19,2 mg
Na++ = 7 mg
K+ = 1,3 mg
HCO3- = 256,2 mg
SO4-- = 16,8 mg
Cl- = 15,5 mg
NO3- = 8,5 mg

My cheap tests show 14° dGH and between 10° and 11° dKH.

If you try this formula
1. If the Ca from test kit is just for Ca, then
Mg = (dGH*17.1 - Ca*2.5)/4.1 (ppm)

you get 19,06. If that is mg/l then it actually works :cool:. But without some reasonable explanation it could be just a coincidence.
 

Roman

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Re: Dosing General Hardness

Tom Barr said:
It's highly unlikely, although remotely possible, you have any GH issue with a hardness of 200ppm. If you did have any issue, adding a small amount of MgSO4 would take care of it.

Regards,
Tom Barr

Hmm, Tom if I have dGH around 14 (degree up or down) then I can asume that I can't have Ca issue. Right? And Mg issue would be probably the last thing I should look if everything else is ruled out. Is this making any sense?