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Discussion Starter · #402 ·
After this week, you do your 50% water change on day 7, you can now start dosing micros and gh booster. Try to get the mg:ca ratio 4:1, but if you have a lot of Ca in your tap water then perhaps you need to use RO water, other wise you will have far too much Mg in the water.
If you have Ca in your tap water, then you don t need GH booster. You can use najas guadalapensis as a bioindicator of Ca lacks.

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Discussion Starter · #403 ·
You are well oriented but,

I just mentioned that the opposite ration seems to work better as a starting point. I just wanted to destroy the myth about the need of high levels of Ca, this is not a universal rule. It is all about the uptake and special needs of different plants. Najas guadalapensis, ammania gracilis, rotala macradra and microsorums needs a lot of Ca, but it doesn´t mean 4:1 Ca:Mg. If you don´t have those plants, then you probably don´t need to add Ca.

On the other hand, Glosso needs a lot of Mg, then the "ratio" is different.

The ratio I suggest can be used as a diagnosis tool to find out when something is really wrong: for example GDA (Algae control approach). If you are adding 4:1 Ca:Mg and 2 ppm of Po4 when you don´t need it, GDA is the obvious consequense.

But for fertilizing the idea is to find out the real needs of your tank, then you have to do the protocols. It is all about uptake and the protocols are tools to know your tank better.

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Re: Method of controlled imbalances and gda...

1) You don't need a Mg test. If you have a GH one then you just need a Ca test: GH - Ca = Mg
Hallo, Christian!

I am afraid I have Mg/Ca imbalance and I would like to verify if it's true. So I measured GH and Ca to find out Mg/Ca ratio. GH=8 and Ca=50 ppm. GH - Ca = -48ppm Mg :confused:
 

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Discussion Starter · #405 ·
Re: Method of controlled imbalances and gda...

Hallo, Christian!

I am afraid I have Mg/Ca imbalance and I would like to verify if it's true. So I measured GH and Ca to find out Mg/Ca ratio. GH=8 and Ca=50 ppm. GH - Ca = -48ppm Mg :confused:
8 gh means 143.84 ppm minus 50 ppm Ca= 93.84 Mg.

Do you have any algae that you can use as a bioindicator?

This is very unusual and there should be a mistake. Do you have this info from the tap water company?

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Check your test kit to see the units for GH. The kits should also give you a formula for converting GH to ppm.

Typically, GH is reported as german degrees general hardness. Those units are different than ppm. To convert to ppm or mg/L, multiply by 17.8. So, GH of 8 is equivalent to 142 ppm of minerals. The Mg portion is estimated to be 142-50=92. Accordingly, your Mg to Ca ratio is ~ 1.8 : 1.
 

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Thank you Christian and nfrank!

Today I found out, that my situation is more complicated than I thought. GH reading I gave you was 3 weeks old, but tap water readings gave my tap water company last week. I just did GH and KH tests today again and was shocked - my tap water has GH=11 and KH=9 now! 3 weeks ago there were only GH=8 and KH=5. Since August 2010 these values were pretty stable (I did tests every 1-2 months). And my tank's water is more harder - GH=13 and KH=11. I called my tap water company and they said I live in place where water line system takes water from 2 different sources - first comes from river and is threated by water purification station, but the other comes from underground source and is much harder.
I bought a JBL Ca test kit today and measured calcium level in my tank. It's 140ppm. So Mg must be about 231,4 (13*17.8) - 140 = 91.4 and Ca/Mg ratio should be 1.53:1

I use GDA as bioindicator. As it has bloomed for about 2 months I started to add KNO3 to my paludarium (~80l of water, CO2 3bps, 4x80W JBL Solar4 fixture 55cm above 13cm deep water) 0,3 grams daily + aquarium fertilizer with KNO3 included without knowing MCI (I thought I had BGA, but later found out that it is GDA). After 4-5th day a few spots of GSA started appear, but GDA was not gone completely. One week ago before water change (50% weekly) NO3 readings was 40-50ppm, but PO4 was zero ppm. My anubias leaves and glosso have green and black spots now. Last week I added only 0,1 grams KNO3 and ~0,016 PO4 daily. On Saturday I did 50% WC and from Sunday I stopped fertilizing and started adding 0,5 grams KNO3 daily to reach GSA and find out my weekly amount of KNO3. before last WC NO3 reading was 10-15ppm, but PO4 0ppm. My main plants (~75%) are PO4 consumers (anubiases, crypts, marsilea and microsorums) I have also glossostigma elatinoides, christmass moss, blyxa japonica, pogostemon helferi and hydrocotyle verticulata in my paludarium. I am afraid that my plants suffer from lack of PO4.
 

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And now it is my turn to battle algae. I have Green Thread Algae overrunning my 12 gl 3-foot tank. The tank is about 6-months old and is about 40% planted with Rotala macrandra and 1 small red tiger lotus. The other 60% are Hemianthus callitrichoides and micranthemum, under 6700K HO H5 39W x 2 lights ~ 8hrs/day, Finnex 360 cannister filter, 100% AquaSoil Africana sand (NO PowerSand), Hagen 88 mini pressurized CO2 kit (grr) at about 25 ppm 24x7, EI-mid-range style fertilization, GH 6, KH 3.

I finally started doing testing and got Ph 5.8, NH3 0ppm, and NO3 of 80ppm (immediate 50% WC + Prime). I did not test PO4 before the WC.

The tank has no visible signs of any other algae, except 3-4 tiny spots of GSA.

I read and re-read this thread several times over the last 3 days. Most of it makes intuitive sense to me. Nevertheless, I cannot claim that I understand the tank's current water condition, macrandra, I understand' is a Ca priority plant and my NO3 is way over the top as it is. Therefore, I'm leery of starting the NO3 protocol.

Any insight is much appreciated. Thank you, Christian et al.
 

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Check your test kit to see the units for GH. The kits should also give you a formula for converting GH to ppm.

Typically, GH is reported as german degrees general hardness. Those units are different than ppm. To convert to ppm or mg/L, multiply by 17.8. So, GH of 8 is equivalent to 142 ppm of minerals. The Mg portion is estimated to be 142-50=92. Accordingly, your Mg to Ca ratio is ~ 1.8 : 1.
google time
according to this http://sites.google.com/site/aquaticplantfertilizer/home/test-kits-and-testing
and this http://www.thekrib.com/Plants/CO2/hardness-larryfrank.html

(ppm dGH - (2.5 x Ca ppm)) /4.1 = Mg ppm
his mg should be (8*17.8-2.5*50)/4.1 = 4.2 ppm.
 

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I dont think this formula from the provided link is correct:
((17.86 x dGH) - (2.5 x Ca ppm)) / 4.1 = Mg ppm​
Its derivation seems to be based on the convention that Ca and Mg are not typically reported as their ion concentations, but instead as carbonate equivalents. So,

if dGH*17.8 = CaCO3 +MgCO3 (all in ppm units)
Then dGH*17.8 ~ = Ca* (41+60) / 41 + Mg * (25+60) / 25,
or dGH*17.8 ~= Ca*2.5 + Mg*3.4

It follows then that Mg ~= [dGH *17.8 - Ca*2.5]/ 3.4

So, the formula would seem to be correct if it said 3.4 instead of 4.1.

Note:41, 25 and 60 are the approximate atomic weights of Ca, Mg and CO3.
Also note that it is not important to compute the concentrations of Mg and Ca if all you are interested in is their ratios. Then carbonate equivalents work fine.

Dont believe everything you read on the internet. I also provide the caveat that i am not a chemist. :)
 

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;) always google when in doubt

from wiki, http://en.wikipedia.org/wiki/DGH
1 dGH is defined as 10 milligrams (mg) of calcium oxide (CaO) per litre of water

Atomic Weight Ca = 40, O = 16, CaO = 56
10 mg/liter CaO contains 40/56 *10 = 7.143 mg/liter of Ca
Atomic weight of CaCO3 = 100
from here http://www.ca.uky.edu/wkrec/Hardness.htm
A CaCO3 value of 100 mg/l would represent a free calcium concentration of 40 mg/l (divide CaCO3 value by 2.5) if hardness is caused by the presence of calcium only. Similarly, a CaCO3 value of 100 mg/l would represent a free magnesium value of 24 mg/l (divide CaCO3 value by 4.12) if hardness is caused by magnesium only.

I dont think this formula from the provided link is correct:
((17.86 x dGH) - (2.5 x Ca ppm)) / 4.1 = Mg ppm​
Its derivation seems to be based on the convention that Ca and Mg are not typically reported as their ion concentations, but instead as carbonate equivalents. So,

if dGH*17.8 = CaCO3 +MgCO3 (all in ppm units)
Then dGH*17.8 ~ = Ca* (41+60) / 41 + Mg * (25+60) / 25,
or dGH*17.8 ~= Ca*2.5 + Mg*3.4

It follows then that Mg ~= [dGH *17.8 - Ca*2.5]/ 3.4

So, the formula would seem to be correct if it said 3.4 instead of 4.1.

Note:41, 25 and 60 are the approximate atomic weights of Ca, Mg and CO3.
Also note that it is not important to compute the concentrations of Mg and Ca if all you are interested in is their ratios. Then carbonate equivalents work fine.

Dont believe everything you read on the internet. I also provide the caveat that i am not a chemist. :)
 

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if dGH*17.8 = CaCO3 +MgCO3 (all in ppm units)
Then dGH*17.8 ~ = Ca* (41+60) / 41 + Mg * (25+60) / 25,
or dGH*17.8 ~= Ca*2.5 + Mg*3.4

It follows then that Mg ~= [dGH *17.8 - Ca*2.5]/ 3.4
I see that the first part of my statement is not consistent with the definition of GH. :)

In fact, the first statement should have been:
if dGH*17.8 = sum of Ca +Mg ( in Calcium carbonate equivalent ppm units).

To convert MgCO3 into "CaCO3 equivalent," the molecular wt of magnesium carbonate is multiplied by 100.1/84.3 = 1.19!

Note:41, 25 and 60 are the approximate atomic weights of Ca, Mg and CO3.
Also, 40.1, 24.3 (not 41 and 25) are the approximate atomic weights of Ca, Mg.

So, the math should have been:
dGH*17.8 ~ = Ca* (40.1+60) / 40.1 + 1.19* [Mg * (24.3+60) / 24.3],
and
Mg ~= [dGH *17.8 - Ca*2.5]/ (3.5*1.19)
or
Mg ~= [dGH *17.8 - Ca*2.5]/ 4.1

Sorry about the confusion. And like i said, dont believe everything you read on the internet :)

IMO, calcium carbonate equivalent is an odd convention. It doesnt take into consideration the other ions that may be associated with Ca or Mg in natural water systems... particularly sulfates and chlorides. So, be aware that there may be some assumptions in the derivation of Mg.
 

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I had originally said
Typically, GH is reported as german degrees general hardness. Those units are different than ppm. To convert to ppm or mg/L, multiply by 17.8. So, GH of 8 is equivalent to 142 ppm of minerals. The Mg portion is estimated to be 142-50=92. Accordingly, your Mg to Ca ratio is ~ 1.8 : 1.
It now seems that my first post above requires a clarification, but the effective answer may not be different!

When i said GH of 8 is equivalent to 142 ppm of minerals, i should have said GH of 8 is equivalent to 142ppm of calcium carbonate equivalent concentration. And, instead of the Mg to Ca ratio, it should have said the Mg hardness to Ca hardness ratio.

To derive the Mg hardness and Mg concentration, the Ca is converted into CaCO3 units, etc.

However, some test kits report the Ca not as Ca concentration, but as calcium hardness. So, 50 ppm Ca hardness may already be expressed as CaCO3!

Then the non-calcium portion is still 92 ppm of hardness, in calcium carbonate equivalent units!
and the magnesium to calcium hardness ratio is still 1.8!

Any comments?

What is important then is to make sure the units are proper and consistent.... and when Christian says the ratio should be 4:1, is it Mg/Ca, MgCO3/CaCO3 or (Magnesium hardness)/(Calcium hardness)?... where for the latter, Mg hardness is expressed in "calcium carbonate equivalent" units. I think that question was raised previously. :)
 

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However, some test kits report the Ca not as Ca concentration, but as calcium hardness. So, 50 ppm Ca hardness may already be expressed as CaCO3!
this is very possible, it needs to be clarified with the manufacture.

What is important then is to make sure the units are proper and consistent.... and when Christian says the ratio should be 4:1, is it Mg/Ca, MgCO3/CaCO3 or (Magnesium hardness)/(Calcium hardness)?...
this is my questions too, lol.
 

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I have done KNO3 protocol successfully. GDA has gone. Next week I added weekly amount of KNO3 divided in 7 parts. I have no algae on glass and decorations now, but my anubias leaves are turning black and some new leaves are in unusually color - very light greenish. My glosso leaves have light yellow color and some of them are falling off and there are a short green algae on some of them. :(
 

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Hi everyone,

I'm hopping to get some help here as I've been fighting algae in my tanks since I set it up last October.
This method MCI has improved it a bit and I thank Christian and everyone else here for that.
Here is what I'm fighting right now:

Tank specs:
120gal - 60in x 18in x 22in
Ligth: 2 x 250W Metal Halides - 6700K
Substrate: 12mm (1/2")of garden soil topped with 70mm (2.5in) of playsand
Water: RO, TDS 150 ( i guess it gets some from sand and ferts, RO TDS is 1)
N03 - 20ppm , P03 - 0.5ppm, Ca ~ 20ppm, FE > 0.1ppm
CO2: pressurized

Now to describe what I'm having right now here are picture:

My mess:







It's not like plants are not periling but alges are as well... :(














At this point I'm desperate and have no idea what to do..

I did KNO3 protocol and I do get GSA.. I add some PO3 and GSA disappears but GDA stays no the glass. You can see it that there is much more GDA where light pendant is closer to the water (stronger light).
I did have what I think was blue/green algae, I used that Blue/Green remover medication and looks like it's not there anymore or is that pearling mess on my sand still Blue/green algae???
Aquarium look pathetic at this point and I'm not sure what to try next. As I said, I've been working on it since last October, is not like I didn't try.

Thanks in advance..
 

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Slobodan,

What kind of filter and what flow rate you have on your tank?
 

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I just did 20 gal water change and I think that mulm at the bottom is Blue/Green algae.
I did blackout for three days 3 times so far. It does disappear but comes back after couple of weeks.
I'm looking for erythromycin right now, it looks like it's only option..
I think I forgot to mention that I also have 25W UV light as well which is on 24/7.
 
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