# Calcium and Magnesium just boiled my brains...



## kenneth_kpe (Oct 1, 2005)

I am trying to cancel out Mg and Ca def. in my tank, I just purchased a JBL Ca and Mg test kit...

Measured my water params and got the ff values.

Mg + Ca = 100 mg/l
Ca = 20 mg/l

therefore Mg = 80 mg/l

I think the "ideal" ratio for Mg to Ca is something like 1 :4 right ?

Question... mg/l --> PPM is 1:1 i think right ??

2nd question..... My Mg to Ca ratio is screwed... and I think if it is in PPM the Mg and Ca contents are pretty high..... 80 ppm Mg and 20 ppm Ca

What boggles me..
The test kits give me a low reading because the color changes after a drop only..I think the JBL test kit is for marine tanks... (the test kit is NEW!!)

HELP!

mg/l == 1 ppm taken from
http://pmep.cce.cornell.edu/facts-slides-self/facts/gen-peapp-conv-table.html

1:4 taken from searching the forums


----------



## kenneth_kpe (Oct 1, 2005)

doh!! i now know why... salt water test kit...

1 drop of Mg + ca will give 100 mg/l...

by my calculation i need to use roughly 180 ml to get a 6.25 mg/l per drop....

Am I correct ? are saltwater levels for Ca ng Mg that high !!!?!?!

I can try to use this by dillting the solution.. the Mg test says I can do so.. but the Ca doesn't and its not giving me accurate results.... this is irritating..


----------



## SnakeIce (May 9, 2005)

If you are reconstituting RO and thus know that you are adding just Mg and Ca you can use Ca levels to find your Mg levels based on Gh. There are other things that generate Gh hardness besides Ca and Mg, so if your water is like mine you can have more non CaMg hardness than there is from those two.


My tap Mg levels are so low as to create Mg deficiency stunting which is alleviated by as little as 2 ppm Mg dosed. I tested 40-60ppm Ca yet my Gh is 120-140ppm. Clearly this is an extreme example, but it shows that using Gh and Ca tests to find your Mg levels is iffy.


----------



## Edward (May 25, 2004)

That would be 20 dGH just by Mg and 2.5 dGH by Ca, total hardness of 22.5 dGH. Something is not right, you need to recheck the values. 

Also, there is no right or wrong Ca:Mg ratio, plants just don't care about it. 

APC FAQ , see GH, Ca and Mg.


----------



## kenneth_kpe (Oct 1, 2005)

thanks for the link edward...

in any case I still cant measure my Ca and Mg levels with the test kit that i have, the sensitivity is just too high, 1 drop == 10 mg/l for Mg + Ca and 1 drop = 20 mg/l for the Ca.....

hmmm should i stop bnothering about my Ca ang Mg... Im starting to rule out everything for the def of my ludwigia cuba.. the only one left is iron..










hmm have to sell this test kit


----------



## hoppycalif (Apr 7, 2005)

The most common deficiency people have is a carbon deficiency - inadequate CO2 or irregular concentrations of CO2. It is a good idea to eliminate that as a problem before pursuing other possible deficiencies. Then, there are nitrate and phosphate deficiencies to be eliminated. Only after those, in my opinion, is it worthwhile to check carefully for calcium or magnesium deficiencies. If you use tap water, the water company water quality report can quickly answer whether you have adequate Ca and Mg. If you use RO water, you can use Equillibrium or Barr's GH Booster and know you have added an adequate amount of both Ca and Mg.


----------



## kenneth_kpe (Oct 1, 2005)

Hi hoppy,

I tried contacting the water company before, being a 3rd world country with a very messy system.. it proved really really futile ahaha

Anyway I might do a 100 percent tank reset, the tank has been sitting for 1 year plus already (when I left it at home for work)... I think the substrate might be too poisoned laready or somoething...

Co2 levels are consistent btw... Nitrate levels fluctuate


----------



## Edward (May 25, 2004)

Hi
With the Ca test kit, do you use 5 ml and then you change the colour of it from pink to violet? If that's the kit then use 10 ml instead of 5 ml and then each drop represents 10 ppm of Ca. This doubles the Ca reading resolution. 

For Mg just test GH in dGH. 

Next,
((17.86 x dGH) - (2.5 x Ca ppm)) / 4.1 = Mg ppm

This gives you Mg level from GH and Ca test. Let us know how it works.

Thank you
Edward


----------



## kenneth_kpe (Oct 1, 2005)

hi edward. tried that one, it still gave me a reading that was too low... when i dilluted the water from 5 to 10 ml and the sensitivity is still high 10ppm of Ca is a bit high right ? I tried doubling the water volume to 20 ml and the color became a bit too faded... right now im selling the test kits to reefers for 1/2 the price i purchased it for.... an expensive lesson i should say hehehe

*side question* do you think under 10ppm of Ca is too low ?

another added piece of info... i was unable to find a Gh test kit....


----------



## Edward (May 25, 2004)

No, you don't want to dilute the tested water. What you want is to use the Ca test kit as is except you use 10 ml instead of 5. This will give you 10 ppm Ca resolution which is quite reasonable for planted aquariums. Each drop represents 10 ppm of Ca if 10 ml is tested. 

So if you have to put at least two drops to change the colour then you are ok as this means that you have more then 20 ppm of Ca. Keeping Ca at 20 -30 ppm works well. If you have less then 20 ppm then CaSO4 will fix the deficiency. 

Hardness GH test kits are the most common aquarium kits available in all aquarium stores.


----------



## kenneth_kpe (Oct 1, 2005)

sorry I did not dillute the water hehe wrong choice of words, the correct terminology would be, I added more water for the test.

I will try to look for a GH test kit.. does this mean I wont be able to use the Mg + Ca test kit at the same time ? Because 1 drop gives me 100 mg/l.... 

*BTW mg/l is the same as PPM right?


----------



## Edward (May 25, 2004)

It looks like you can use the Ca kit at 10 ppm resolution, but not the Mg kit. You can also calculate Mg levels if you know GH and Ca. Yes, mg/l is the same as ppm.


----------



## kenneth_kpe (Oct 1, 2005)

thanks ! i will try to sell this test kit first, if nobody bites then I will use the Ca part.


----------

