Re: [AGA-Member] Magnesium nutrient issues

[Larry Lampert <l_lampert@yahoo.com>]

Heather,

A couple of comments and a couple of questions....
You stated:

> > advise. dGH - dKH = additional alkaline metals
> such as Na, Mg, and so 
> > on.  One point of the difference is the soda I've
> been adding.  Local 
> > waters are alkaline but not dolomitic, so I'd
> suspect the remaining 
> > point, from the source tapwater, is also mostly
> sodium.

Magnesium and Calcium are components of GH. The
alakaline earth metals are the would be like barium,
or other rare elements. These are not commonly seen in
measurable quantities in tap water in the US.

As far as I remember Sodium does not add to alkalinity
anyways. It does of course add to TDS. If you are
concerned with Na levels contact your local water
utility and ask for a copy of their annual water
report.  

I am also not sure about your magnesium ratios you are
trying to chieve. CA and MG are macro elements. The
plants use them for osmotic balance as well as
consuming themin trace amounts. The ratios between CA
and MG are usually 4:1 or 3:1. I think what you read
on Chuck's page was the minimum amount of 5-10 ppm MG.

Increasing the MG will increase your GH but it will
NOT
affect your buffering capacity. If you add a carbonate
or bicarbonate like baking sode that will increase
your alka;inity or the ability of your ater to resist
a downward change in pH.

If you are concerned with your CA:MG ratios you can
use Seachem's equilibrium instead of the dolomitic
lime and epsom salts. Equilibrium will give you a
correct ratio out of the jar. I would contine to use
Baking Soda for raising Alkialinity unless you do
indeed have an elevated level of soium in your water
like Cheryl does. I would not assume this to be the
case until I read a water report.

I think you should just raise the GH to 4-6 by using
equilibrium and just forget about it. It is one thing
less to worrry about while you are trying to dial in
your traces.

Currently your CO2 according to the chart @pH 7.4, dKH
4, dGH 6 is only 4.7. This is still your main problem.
You need to push your CO2 up to 20-25 and then you
will likely have to readjust your traces as consuption
goes up. 

I also use Fe (.2ppm) as the proxy as recommended by
Tom Barr, Roger Miller and others to set my trace
levels. You are going to get your traces in line AFTER
you get the CO2 issue resolved. Once this is done then
you can start fine tuning your dosing and water in
relation to the amount of light and depth of your
tank.

You also have a lot of light at nearly 4 watts/gallon.
You may want to dial it back to a little less than 3
watts/gal until you get your tank balanced. Remember
that the more light and CO2 you have the more traces
you will need to be available to the plants so the
less margin you have for error in your dosing.

Regards,
Larry Lampert
Dallas, TX

 
--- Cheryl Rogers <cheryl@wilstream.com> wrote:

> No one ever answered this. What a drag. I was
> looking forward to it.
> 
> Cheryl
> 
> Heather J Gladney wrote:
> > 
> > My 90 gallon tank (actual gallons about 76) has
> lots of long stringy 
> > algae,BBA, and one large old SAE.
> > As it's a tall hexlike diamond shape, I've got
> power compacts on it, 2 X 
> > 55 watt and 2 X 96 watts, for total 302 watts, or
> not quite 4 
> > watts/actual gallons.
> > It generally has 0 nitrite and about 12 ppm
> nitrate, probably due to 
> > fish + food.
> > I'm not certain how many inches of fish it has
> because the Corydorus 
> > catfish breed in there, and I keep finding new
> babies.
> > It used to have CO2 injection issues, and CO2 was
> off completely for 
> > about 2 weeks.
> > I'm trying for a community tank balance, as I'm
> keeping both Cardinal 
> > tetras (soft acid water) and Cryptocorynes that
> like hard alkaline water 
> > (bad owner!!).  In fact, the C. balansae grew
> better when my CO2 line 
> > was down.
> > I think I finally got the CO2 supply fixed this
> weekend, thanks to 
> > helpful advice from folks here.
> > 
> > Now I'm thinking about the nutrient dosing to work
> on that hair algae 
> > and BBA.
> > I'm coming up with some odd numbers on Epsom salts
> from the ratios that 
> > people suggest.
> > 
> > Normally, with CO2 injection, the tank was at pH
> 6.8-7.0, dKH 5-6, dGH 7-8.
> > Without the CO2, the tank went up to pH 7.4 - 7.8,
> same dKH and GH.
> > Tap has KH 2, GH 3, so some months ago I started
> adding powdered 
> > dolomitic limestone (from Greg Watson) and baking
> soda to bring makeup 
> > water one point each to dKH 3, dGH 4.  This isn't
> as high as some 
> > advise. dGH - dKH = additional alkaline metals
> such as Na, Mg, and so 
> > on.  One point of the difference is the soda I've
> been adding.  Local 
> > waters are alkaline but not dolomitic, so I'd
> suspect the remaining 
> > point, from the source tapwater, is also mostly
> sodium.
> > Which says there's hardly any Mg in there.
> > 
> > Awhile back someone reminded me of Tom Barr's
> advice, and suggested 
> > bringing up dKH to 4-5 and add some soda for
> better pH buffering.  
> > Because of that, and to better match the tank's pH
> without any CO2 
> > injection, on my latest 30% water change, I
> doubled the limestone and 
> > soda amounts as I got the CO2 injection going
> again.
> > Now, with CO3 injection started, the tank tests at
> pH 7.4, dKH 4, dGH 6.
> > The difference is 2 points, just what you'd expect
> from doubling my 
> > previous soda amount in the makeup water.
> > I also added fertilizers that include macros, Mg,
> Fe, traces, and so on, 
> > but clearly not enough Mg to affect the dGH-dKH
> hardness difference very 
> > much.
> > As I adjust the CO2 injection, I'll bring that pH
> down gradually to 
> > 6.8-6.9 to get better CO2 percentage.
> > But perhaps I ought to increase my limestone and
> Mg amounts too.
> > That made me start to recalculate my dosing drops.
> > 
> > Please correct me if I'm wrong, but could I
> increase dGH by skipping the 
> > soda and adding Epsom salts for Mg instead?  This
> should increase 
> > general hardness for buffering the pH, and the
> plants would like Mg 
> > better anyway.
> > I thought of this because I saw comments noting
> that the ratio of lime 
> > to Epsom salts should be roughly 4:1, or:
> > CA(CO3) : MgSO4, should be 4:1, which ties my dKH
> to how much Epsom 
> > salts I add.
> > 
> > Working from "the ideal Mg amount":
> > My hardness test kit instructions show 17.9 ppm =
> 1 degree for both dKH 
> > and dGH.
> > Chuck Gadd's nutrient calculator page suggests the
> guideline of 5-10 ppm 
> > of Mg, but other comments suggest it can be more.
> > If I maintain the ideal Mg of 5-10ppm, that 4:1
> ratio gives 20 - 50 ppm 
> > CA, or dKH =1.1 - 2.8, which I thought was pretty
> soft water.  A lot 
> > softer than what I've got going!
> > But list comments note that many plants like hard
> water, that it can go 
> > higher.
> > 
> > Working from the hardness I've already got:
> > With current dKH of 5 - 6, or 89.5 -107.4 ppm Ca,
> a 4:1 ratio that gives 
> > 22.38 - 26.85 ppm Mg.
> > That is double the high recommendation.  Also, it
> requires adding 4 - 
> > 4.5 tablespoons of Epsom salts dry directly to the
> tank.
> > This sounds like an awful lot!
> > It also adds that same amount of sulfur, and I
> planned to add sulfur 
> > elsewhere by using potassium sulfate (K2SO4) as a
> K source.
> > (I don't want to use KNO3, because the N is plenty
> high in this tank 
> > right now--I hope that it'll go down if I can get
> the plants growing 
> > better..)
> > Do we have any guidelines on how much sulfur is
> too much?
> > Also, how much change in dGH does that much Mg do?
>  Don't think I'd need 
> > to add any baking soda, though!
> > 
> > Whic leads down to the final question, would it be
> okay to push up the 
> > Mg to keep the ratio with Ca intact, or should I
> leave it at Chuck's 
> > 5-10 ppm and a lower calcium amount and lower dKH,
> which I suspect the 
> > fish would like a little better?
> > 
> > 
> > 
> 
> -- 
> Cheryl Rogers, Membership
> Aquatic Gardeners Association
> http://www.aquatic-gardeners.org
> _______________________________________________
> AGA-Member mailing list
> AGA-Member@thekrib.com
> http://lists.thekrib.com/mailman/listinfo/aga-member
> 

_______________________________________________
AGA-Member mailing list
AGA-Member@thekrib.com
http://lists.thekrib.com/mailman/listinfo/aga-member