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Re: [AGA-Member] Magnesium nutrient issues

Larry Lampert wrote:

Hi Heather,

The old Krib Archives are a goldmine of information
for those interested in doing the research. We can all
thank Erik Olson for that!

Loud "yes, thank you" from this chair, too!

I am not sure what part of the country you are in but
for reference purposes.

Central CA, considered fairly arid, but not desert--we end up living off snowmelt in mountain reservoirs.

My water comes from 3
reservoirs here in Dallas so it to can vary. I measure
my GH with a Lamotte kit. It comes out to around 5.5
Gh, to be exact when I do the calcium test and the
Magnesium remainder it comes out to 96-98ppm total GH
with 90-94ppm CA and around 4-6 MG. Yes, my CA:MG
ratios are way out of whack too. I use two teaspoons
of Mg2SO4 for each 30 gallons of water I change. This
gets me to about 138ppm total of which the Mg is now
around 48-54ppm.

This is helpful, because I'm seeing something I may be doing wrong.
Using Chuck Gadd's calculator program (another big thank you!) when I run your figure of 2 tsp of dry MgSO4dry in 30 gallons (as if I was adding it to a 30 gallon tank), I get 9.38 ppm.
You already have 4 to 6 ppm of Mg in the makeup water. That totals to 13 - 15 ppm in your makeup water, right?
But if I run 2 dry tbsp in 30 gallons (just in case you meant tablespoons, not teaspoons) then I get 28.14 ppm.
Which would total to 32 - 36 ppm, which still doesn't match your numbers.
Where is the 48 -54 ppm Mg coming from? Is my version of the downloaded program corrupted, perhaps?
This is partly why I've thrown out the Mg question to the list!

It is not exact since my teaspoons are not always
measured exactly level. I have not seen any
reproducible benefits from going any higher or lower
with MG ratios. IME if I keep the ratio at 1:3 or 4 it
is all the same. I have not gone any higher than 1:2
as Jeff discussed so I don't know what would happen
but I have used straight tap water and my plants did
indeed have deficiency symptoms.

The last piece of advice is to not trust test kits
implicitly. The reagents go bad over time in the best
of kits, and many pet store grade kits don't seem to
work at all. Indicator plants ie. Rotala, Ammania, and
many others will let you know if you have a nutrient
deficiency every time as long as you know what to look

I could never get Rotala to grow, either before or after CO2.. It acted as if it was in a low light tank buried down in the dark at 20" deep, and rotted out on me. Hadn't tried Ammania, as I assumed as a high-light plant it would have similar issues.
Now I'm wondering if the light isn't the problem, but Redfield-ratio etc.

More good info on this on the Krib and APD
archives too!

Reading your posts it sounds like you are on the right
track. Let us know how the tank progresses.

Thank you again--I will.

Larry Lampert

--- Heather J Gladney <hgladney@comcast.net> wrote:


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