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dennis said:
OK chemistry people:

I just got a LaMotte Ca test today and 2 runnign 2 tests I get the same answer of 95ppm Ca, read as ppm Calcium Hardness as CaCO3.

In the following equation used to find the ppm of Mg, does the Ca in ppm number need to be converted from my reading of 95ppm as CaCO3? If so, I would divide by 7.143?

GH in ppm - (2.5*Ca in ppm)
--------------------------- = Mg in ppm
4.1

Any help is appreciated!
Your Ca is 95ppm x mol CaCO3/ mol Ca = 40.08+12+3x16/40.08 = 2.5
95/2.5= 38ppm Ca++

The above equation off hand appears right.

Say the GH (total hardness as CaCO3) is 120ppm.
120-95 = 25ppm Mg as CaCO3 equivalents.
25/4.1= ~6ppm Mg.

I'd not bother with this, knowing the difference between a few ppm in a ratio is not going to do much for you unless you desire to add very small, potentially limiting amounts.

Nothing I've found suggest a ratio of Ca/Mg does much, the amount of error in our testing and habits plays a much more significant role I would suggest.

Add a little of both Ca/Mg to your tank each week beyond the amount of plant growth requirements, say 10ppm of Ca++, and perhaps 4ppm of so of Mg++ and you are set. That's in addition to the Mg/Ca in your tap water, other sources.

Regards,
Tom Barr

PS-
I recently bumped my Mg up with Rotala wallichii, unlike Edward's photo's, it did not stunt. I am using soft water(KH = 2) and low GH's.

5.4 grams in 1 teaspoon of MgSO4*7H2O.
9.9% of it is Mg.
So per gram of Epsom salt added to one liter: 9.9/100= 99 ppm or mg/L.
So per gram added to a 75 liter(20 gal tank) 99ppm/75= 1.32 ppm Mg++.

5.4 x 1.32 ppm= ~7ppm of Mg.

I added 1.5 teaspoons, a fair amount of Mg to such a small tank.
10.5ppm and that does not include the fraction for the tap.
Generally 1/4 to 1/2 teaspoon per week will address any Mg issue.
But those with higher GH's, likely can use more if they want without issue.

I have not done enough with Mg to say much still.
I only did the Rolata test once. I waited for 3 days after.
So who knows just yet.

Still, adding the rec's I suggest are fairly light, not excessive, if you apply the EI notion to 2x the weekly build up if no Mg is used, then the amounts end up in the 2-6ppm range generally.

Folks have been using Mg in PMDD and with other mixes for a long time.
I tend to suggest a few degrees of GH for soft water, about 3-4 at least using SeaChem EQ or the Gh booster, folks with harder GH waters may need some Mg or Ca to balance things out so neither is limiting.

I think you can approach it that way, using just GH and adding a bit more with a balanced product or................you can analyze GH individually into the Ca and Mg sereprate nutrients.

I'd stick with one method though, that will simply things.
At the end of the day, I do not think you will see marked differences with either method.

Both can supply the required amounts of Mg and Ca.
One test more, the other uses a GH kit or none at all.

Simply because you do not test, does not mean you need to know what the ppm of Ca/Mg, only that you have enough to prevent limiting conditions.
That's the real issue for 99% of aquarist, not confusing themselves with test kits/methods.

Why test unless there is a problem?
How do you avoid such problems to begin with?

Pretty straight forward.
If you suspect K+ is limiting, then add more K+ and see.
You do not need to test the K+, you can if you want, but you do not need to do so to know the K+ is limiting or in excess. Simple calculators will tell you that.

Regards,
Tom Barr
 

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plantbrain said:
I see too much confidence in folk's reports of CO2 levels and reports of very wide ranges of CO2 ppm readings for it NOT to be a huge issue.
Well I do think I can cross that one off, as I use a calibrated pinpoint probe, and don't measure KH. A sample of my tank water goes up 0.8-1.0 pH points with a few hours of vigorous aeration with an airpump, Ive found that to work pretty well. Other than upping the dose of calcium, I've backed off on my trace a bit, maybe its not a deficiency but a toxicity issue, whatever the problem it's (a) hard to reproduce and (b) only affects the fussiest of plants. Mg/Ca ratio is a good scapegoat, it will one day mysteriously get better, I'm sure of that. A "heisen-bug" if you will. And the whole exercise is a bit pathological as I would easily sub in one of the 300 other plants I can grow well :)

Jeff
 

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Tom,

That's the first time I have ever seen you do math! Not that you don't do math, just never seen you type it all out. Now I feel special :)

Jeff, you pring up a good point regarding using a pH shift rather than kH to measure CO2. In my case, fully settled tank water is 7.0 but by 6.5 fish are gasping. This stress does not happen right before lights, and CO2, come on, as I would expect but rather midday once the CO2 has been cranking for a couple hours. The increased lighting period I run midday creates some extra O2, visable as heavy pearling, but this obvious sign of O2 saturation does nothing to alleviate fish stress. I can only assume from this thathigh CO2 levels are to blame. However, this does not explain the only .4-.5 pH drop the tank can handle.

Incidently I use the intank diffuser method with lots of mist.

I think I may have to do some mucking with surface movement but anymore turbulance and I will get whitecaps!

Tom,

Thanks for all your help with this. It seems that my water parameters are definately within the limits with nothing excessivly low or high, much as you assumed it would be. I may try just adding some GH Booster or Equilibrium but I really wanted to pinpoint this, if for no other reason than personal satisfaction!

Jeff, I orignally though via other's suggestions that possibly I had a high Mg affecting Ca, as unlikely as that was. Plus, the fact that only new growth and not old growth was affected pointed to immobile nutrient deficiency. However, providing I have calibrated my GH test correctly and done all the math correctly, my Ca and Mg are definately in good shape.

So, what are our other options....
a)faulty test readings
b)CO2 fluctuations/limitations Do you turn off the CO2 at night?
c)Toxicity of some trace element
d)Low K
e)Low some other trace

Any other possibilities?

Oh, and
And the whole exercise is a bit pathological as I would easily sub in one of the 300 other plants I can grow well :smile:
But that would mean admitting defeat! :)
 

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JLudwig said:
Well I do think I can cross that one off, as I use a calibrated pinpoint probe, and don't measure KH. A sample of my tank water goes up 0.8-1.0 pH points with a few hours of vigorous aeration with an airpump, Ive found that to work pretty well. Other than upping the dose of calcium, I've backed off on my trace a bit, maybe its not a deficiency but a toxicity issue, whatever the problem it's (a) hard to reproduce and (b) only affects the fussiest of plants. Mg/Ca ratio is a good scapegoat, it will one day mysteriously get better, I'm sure of that. A "heisen-bug" if you will. And the whole exercise is a bit pathological as I would easily sub in one of the 300 other plants I can grow well :)

Jeff
One measurement or two in time means little, you need to keep track of the CO2 over the course of the treatment.
At least one full day of observation and then thereafter am/pm or if anything is funny looking.

It's nothing like NO3 at 20ppm.
In 30 minutes a tank's CO2 can drop fast.
Many things influence CO2.

The more I know, the more I doubt.
Uncertainty is high is all.
I've seen evidences of CO2 ppm changes throughout the day on many tanks.
I'm very leery of CO2.
I play with that much more than any single nutrient.

I can help with the toxicity issue.

I added 200mls to a 20 gallon tank of Flourish, not 20, but 200mls.
The water was very dark and stayed that way over the 3 day peroid.

No stunting, not shrimp issues, nothing relatable to toxicity was ever observed. I used TMG to dose to 2ppm of Fe a decade ago, I had very good plant growth.

Regards,
Tom Barr
 

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dennis said:
Tom,

That's the first time I have ever seen you do math! Not that you don't do math, just never seen you type it all out. Now I feel special :)
Don't.
I scare folks with talk, add math and they really cringe.
I've posted plenty in the past that details out Chemistry.
There are links all over going pretty far back.

However, this does not explain the only .4-.5 pH drop the tank can handle.
Well, that right there explains a lot of your tank's issues, more than the Ca/Mg thing.

You can change this by adding more surface movement, a slight rippling is good, flake food should move around the surface but not be torrented under the water.

I think I may have to do some mucking with surface movement but anymore turbulance and I will get whitecaps!
Then white caps it is.
But........the testing method for pH............what are you using? Get a pH pen or monitor if you do not have one.
Most everyone can knock it down a full pH unit without issue.

I may try just adding some GH Booster or Equilibrium but I really wanted to pinpoint this, if for no other reason than personal satisfaction!
Well, careful of what you wanna know there.

Plus, the fact that only new growth and not old growth was affected pointed to immobile nutrient deficiency.
Low CO2 suddenly also causes the same expression, stunted smaller growth of the vegetative tips, is CO2 a mobile or non moblie nutrients?:)
This is a trick question.

a)faulty test readings
b)CO2 fluctuations/limitations Do you turn off the CO2 at night?
You can easily rule out the K+ if you use KNO3.
Traces: see previous post.
They are traces, while needed, they have a wide range, and the expression is very difficult to prove in isolated studies of what the stunting might look like. Measuring tiny tiny amounts is very difficult except in highly controlled studies.
Toxicity has never been show in aquariums with Flourish or TMG to my knowledge. I certainly have been unable to show it when dosing even 10x the normal high dosing amounts.

So focus more on a and b. That and the pH drop says a lot.
Don't worry, even the best get nailed with CO2.

BTW: here's why the K from KNO3 is unlikely to be an issue in terms of limitation:

http://www.aquariacentral.com/forums/showthread.php?t=21033

One poster had a common error, but it was caught and corrected.
Unless you have nearly 75% of the N coming from some other source, such as fish load or tap, it's very unlikely you need extra K from K2SO4.

Steve Dixton postulated both the K was enough from KNO3 alone and that adding Mg was more critical than we thought.

He said that to me back in 1997.

Regards,
Tom Barr
 

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dennis said:
a)faulty test readings
b)CO2 fluctuations/limitations Do you turn off the CO2 at night?
c)Toxicity of some trace element
d)Low K
e)Low some other trace
Dennis I use a JBJ solenoid so its only 12 hrs of CO2 a day. I could run the CO2 all night and see what happens, when I had no trouble with the rotalas (I've got the plantfinder picture of the same plant giving me guff right now, go figure :) ), I was on a 24 hour cycle. Hmmm....

With respect to your problem I would get to the bottom of that pH issue ASAP. Something is wrong with your pH measurement, it sounds like the gain on your instrument might be out of whack. When was the last night you bought a new probe?

Low K? Don't know, K is immobile IIRC so not sure that would cause stunting in new growth.

Jeff
 

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JLudwig said:
Dennis I use a JBJ solenoid so its only 12 hrs of CO2 a day. I could run the CO2 all night and see what happens, when I had no trouble with the rotalas (I've got the plantfinder picture of the same plant giving me guff right now, go figure :) ), I was on a 24 hour cycle. Hmmm....

With respect to your problem I would get to the bottom of that pH issue ASAP. Something is wrong with your pH measurement, it sounds like the gain on your instrument might be out of whack. When was the last night you bought a new probe?

Low K? Don't know, K is immobile IIRC so not sure that would cause stunting in new growth.

Jeff
Jeff,

Yes, the pH/CO2 issue has become my new priority. I tried cranking the CO2 a bit more by lowering the set point of my monitor down a little. I also increased the surface flow a little and added a PC fan to my hood to try and promote air movement over the water's surface, there by increasing O2 and reducing fish stress from adding more CO2. All the fish were alive when I got home tonight but that does not mean they were not stressed while I was gone. Lights have been off for about 2 hours and pH is 6.6.

I have not replaced the probe in about 1.5 years (technically never replaced the probe as I bought the unit new then). I have observed the readings with lights on, lights off, in fact with all power to the aquarium off save for the controller itself. Never a change in readings and I have done this several times, once very reciently. The probe calibrates very easily, never straying more than .1 in a month and always tests right to 7(or 6.9 depending on how long it was since last calibrated) when checked with a new sachet of pH 7.0 calibration solution. I have checked this and checked this and checked this and it does not seem as though the probe is bad. I even once tried sealing the probe up in a sachet for several hours to see if it wandered then...nothing. I suppose I could get a new probe but at $50... I may try running without the controller and just go by bubbles count and observation.....

Any recommendations for a starting bubble count on a 50 gallon, lots of surface movement and in tank ceramic diffuser?

From my reading K is mobile so low K would not affect new growth; however, I have also read that low K can reduce uptake of Ca, not block but reduce through slowed growth. K is also major in root development and stomata regulation (I think). I have noticed a signifigant decrease in root development in most of my plants over the last couple months, especially Bylxa japonica, which was usually a strong rooter, HC, aswell as Lobelia and stems like L cuba and P stellata, which used to produce extensive roots. There are no "aerial" roots comming form the Rotala's. My tank gets 4x week dose of 10:6:.5 NKP via GW ferts, or 40ppm NO3, 24ppm K and 2ppm PO4. I know I am dosing that so it doesn't seem like low K is an issue, nor low Ca, nor low Mg, or high Mg..... Also, the lowered rooting could be that the tank is more mature now and the plants not needing to resort to substrate nutrients due to plenty of water column nutrients. I just don't know.

Must be a CO2 thing:(
 

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Well,

I ate some crow Thursday, boy was it good. I saw the sticky in the equipment forum about testing pH probes. Turns out mine must be bad. Only hit about 8.5 in the Windex, soaking an alcohol and then rinsing/recalibrating only made it worse. It tested immediatly to 7.o in the bufer solution though.

Fool me once, idiot:)

So I increased surface movement as much as possibe, I'll not get more without using an extra powerhead but Eheim 2217 on a 50gallon should be sufficient! I also added a PC fan blowign across the surface of the water thinking I may not have been gettign good air diffusion in my canopy. Lastly I cranked the CO2 even more.
 

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Very interesting thread to say the least.Andif I may interject a few photos of what is going on in my tank..this is the link HTTP://community.webtv.net/victory_life/75gallonIT is to highlight the problem I am having with a few plants,but mostly a sword.the leafs are coming up quick,but they are coming up white.
It seems to possibly be a mag/cal deficit I a thinking or maybe even iron.
the tank has been set-up for about 2 months.and here was my last weeks dosage.
feb 13th.0.58ppm of kno3 as potassium nitrate.
14th.same kno3 and 2 ml. flourish trace
15th.same dosage of both
16th.same dosage..
my water is very hard out of the tap,well water in N.E. oklahoma..s I was adding ro water to cut it..well I may of cut it too much although would still ge moderate readings on my dip-stick..I know probaly not he best way to test,but no pet stores close...
anyway,,yesterday the 18th.. did a 20 gallon water-change and am going to stay away from the RO water for a few weeks and see what happens..
today I added for ferts.feb 18th.
1/2 tsp. of potassium nitrate
15ml. of flourish
10 drops of fleet..(thats a whole lot of fun buying at the store)..LOL
and 1/4 tsp. of epsom salt.
I do not currently have any iron supplement to dose.although I did put aroot-tab from aquarium plants.com at the base of the sword as well as afew crypts.and also have laterite mixed into a gravel base.
no major algae problems to speak of,although have some green spot.
the last dosages I did am going to stick with for a few weeks and see what happens.although any advice would be very helpful...also,only o my hygro poly and hygro "sunset" getting the small holes on the old growth leaves...
If anyting I hope these pics help others to see what some nutrient deficencys look like..and to hopefully get me some answers....
Thanks all.
peace and plenty,
ZENFISH
 

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Edward,

Your PPS recommendation is 5-10 ppm of Mg. Can You comment?

I suspect Ca/Mg issue on my plants (RO user) and need more info on it.

My Mg/Ca is 4/25 and I have curly leafs now.
 

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Zenfish:
That tank looks trace limited to me, switch to TMG since you have hard tap water. Add a tad more CO2. Not much, maybe .1pH unit further down.
You also need to add some more PO4/NO3.
Low nutrients and stressed plants.

Dennis, welcome to the real world of low CO2:) Somewhat humbling huh? If you have not been there, just wait a awhile, everyone that's been in the hobby long enoyugh goes down this road. Many still fight it and think their CO2 must be in good shape and thus chase funny nutrients issues around.

Look at plants more, distrust test kits=> they should have to prove to you that they are accurate and correct.

Elkmore, add good CO2, add more Traces, set things up to isolate the Mg or Ca, do this by providing non limiting conditions for the other nutrients.

You can see if the Mg is the issue by doing this and adding everything but Mg, wait about 2 weeks and you should see the signs of Mg limitations.

Then look very carefully at how the plants grow and which species are effects etc. This will give you a better cause/measurement approach than the guessing and chasing after each nutrients.

It's fairly easy and straight forward.
You can do this for any nutrient easily.

Regards,
Tom Barr
 

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Elkmore,

Consistency and Time.

Changing NO3 from 30 ppm to 20 ppm doesn’t affect plants. But changing Mg and Ca does. You need to maintain stable levels for longer period of time and allow plants to adjust to the new conditions.
It is easy for Ca. Dose once to 20 ppm and re check after a month or so. Mg needs to be dosed daily in rather smaller quantities not allowing it to accumulate. Plants will grow well even if Mg reading is at zero.


Edward
 

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I have not seen any definitive patterns as of yet to that effect.
Some have suggested it goes away when they added more Mg.
Same has been said for Traces, NO3, CO2 etc.

Few seem willing to trash their tanks/plants in a controlled manner to answer such questions. Those with ther ability to do that, don't have the curly leaf issue to begin with and have the control, those with curly leaf, often do not have the control the begin with(ability to confidently rule out another possible confounding cause).

Later this summer I'll have time to set and few things up for Mg.


Regards,
Tom Barr
 
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