Roger Miller aproach of 1:033 NO3 to K ratio and no K2SO4

[freemann]

Check this thread:
http://aquabotanicwetthumb.infopop.c...p;m=8706087912
Could that be the case and do we really dose to much K?

[juggler]

I have a similar problem in a low bioload tank. The tank exhibited Mg and Ca deficiency. Very weird. I think the 20ppm K added weekly could be too much already. Will be lowering that to see if things improve.

[illumbomb]

Interesting article.... so sld we dose with K2SO4 at all??? hmmmm...

[vinz]

I've been following the few threads at AB on K, Ca and Mg since yesterday. I'm still a little confused, but I think 20-30ppm a week of K maybe overdoing it, unless your Ca and Mg levels/dosing can match at the proper ratios.

My action plan for my tank now is to stop dosing K2SO4 for now, monitor GH levels (which are around 18dGH) and observe for deficiencies in K, Ca or Mg. After about half year of high K dosages and no idea of the consumption, I got a feeling K levels have stablised at as high as 100++ ppm. Tap water at my place is at about 6dGH, and I'm wondering what is the Ca:Mg ratio and how I can find out.

[freemann]

Vinz check this:
http://www.animalnetwork.com/fish2/a...io/default.asp
notice this detail:
There is another way to exploit the solubilities of these hydroxides of these
ions to get at the magnesium concentration, but this involves doing two
EDTA titrations rather than one. This is often referred to as the difference
method, in which the total concentration of divalent cations is determined by
EDTA titration as a first step. In the second step, the magnesium ion is
precipitated with a strong base as magnesium hydroxide, and a second
titration is performed to give the sum of the Ca++, Sr++, and Ba++
concentrations. Because Ca++ is by far the most abundant of those three ions,
within the experimental errors of test kits in the hobby this gives the calcium
concentration.

We have verified this to be a fact in an aquaculture chemistry book, maybe magnesium hydroxide could be replaced with another strong base like ammonia.

Also this article that came in my attention by miller is very interesting:
http://www.hydrofarm.com/content/art...ors_plant.html
Notice the ratios of K in relation to N:

Table 1. Internal Concentrations of Essential Elements in Higher Plants
Concentration in Dry Tissue

Element ppm %

Hydrogen 60,000 6
Carbon 450,000 45
Oxygen 450,000 45
Nitrogen 15,000 1.5
Potassium 10,000 1.0
Calcium 5,000 0.5
Magnesium 2,000 0.2
Phosphorus 2,000 0.2
Sulfur 1,000 0.1
Chlorine 100 0.01
Boron 20 0.002
Iron 100 0.01
Manganese 50 0.005
Zinc 20 0.002
Copper 6 0.0006
Molybdenum 0.1 0.00001

Also on the section on potassium

A critical balance is required between potassium, calcium and magnesium or plant stress occurs when the level of potassium is high in comparison to calcium or magnesium. High levels of potassium in solution may induce a calcium or magnesium deficiency. Care must be taken to maintain the proper balance between these three elements.

also in Karen Randall article Plant Nutrition — Part 1
notice the percentage of K to N

Minerals Necessary for Optimal Plant Growth*


Macronutrients
Mineral Approximate concentration
Carbon (C) 43 percent
Nitrogen (N) 1 to 3 percent
Potassium (K) 0.3 to 6 percent
Calcium (Ca) 0.1 to 3.5 percent
Phosphorus (P) 0.05 to 1 percent
Magnesium (Mg) 0.05 to 0.7 percent
Sulfur (S) 0.05 to 1.5 percent

Micronutrients

Mineral Parts Per Million
Iron (Fe) 10 to 1500 ppm
Chlorine (Cl) 100 to 300 ppm
Manganese (Mn) 5 to 1500 ppm
Zinc (Zn) 3 to 150 ppm
Copper (Cu) 2 to 75 ppm
Boron (B) 2 to 75 ppm
Molybdenum (Mo) Trace

*Dry weight in entire plant

I hope all this help

[juggler]

Check out these 3 sites meant for land plants/crops, but I believe also similar for aquatic plants somewhat:

http://www.rodsgarden.50megs.com/plantnutrients.htm
http://foliarfert.com/pages/TRACE%20ELEMENTS.htm
http://www.uog.edu/soil/fertft1a.html

They all mention that excess K causes Mg and Ca problems.
They also mention the effect of excess nutrients on plants.

[Plantbrain]

I'll tell you all like I've told everyone, where is this inhibition if this is true in all of my tanks and all the folks in the sfbaaps club for last few _years_?

Folks, we have low Ca and Mg tap water and have been adding loads of K+ way beyond 20-30ppm for YEARS. I've gone to at leats 50ppm, others even higher.

If this occurs why has it not been happening before?
Suddenly some one says something off a hydroponics site and everyone seems to rush in and say "me too".

Are soil and hydroponic solutions ANYTHING like aquariums and their levels?

I ask, if this occurs, where is my stunted plants(every single plant species folks have mentioned thus far I have kept for long periods with high K+).

So I can vouch for each plant.

It's easy to prove something is wrong. It's much more difficult to prove it is RIGHT.

I can prove this is wrong, now show me how their argument is right in a planted tank.

I have about 8 years and 2 dozen other aquarist who have some damn good test kits(all Lamott and/or Hach) and pure water/reagents to play with that will disagree. Erik won the AGA contest with a bunch of Ammannia and loads of K+ and pretty low Ca. I've grown massive stands of it, so has Neil Frank and others with low Ca/high K+.

Maybe the plant fairy comes and visits me at night to bless my plants? Maybe my tap water wherever I live becomes magic?

Theory from other fields and applications is great, but.....then there's the practical side.

Folks are quick to blame problems on the wrong players rather than trying to figure out WHY their routine is not working. Most often it's from not adding enough or not adding enough regularly. Sometimes from junky test kits. These are some of the practical side roads I've already been down many years ago.

It will not hurt to keep K at 10-20ppm(vs 20-30ppm) and high Ca levels either. But it's not the reason for poor plant growth.

Regards,
Tom Barr

[geoffrey]

Those were all very good info.

In the link, www.animalnetwork.com/fish2..., it shows how the availiability of Ca and Mg divalent cations can be determined. I'm wondering aloud whether the way I used it to calculate their availiability using KH and gH in freshwater planted aquaria is correct.

Assume I have gH @ 20dKH and KH @ 6dKH. Since the illustration in the link uses ppm, I converted dKH into ppm by multiplying 17.8. (1dKH ~ 17.8ppm CaCO3). Right?

Hence, 356ppm total hardness as CaCO3 and 107ppm carbonate hardness as CaCO3. As shown, to get Mg concentration, we less 107ppm from 356ppm, giving us 249ppm Mg++ as CaCO3. Am I right so far?

Now, converting Mg++ as CaCO3 to Mg++, I take 249ppm by 24.305 over 100.09 giving me 60ppm of Mg++. And as for Ca++, 107 x 40.09/100.09 = 42ppm of Ca++. So my tank has 60ppm of Mg and 42ppm of Ca, correct?

1) Am I correct in the first place converting dKH to ppm for both gH and KH by just multiplying 17.8?
2) Is carbonate hardness also calcium hardness?
3) Since total hardness measures, bicarbonates, carbonates, sulphates etc, in the water, are our gH kit measuring that or only bicarbonates and carbonates?

[bclee]

Tom, I am not saying "me too" for the sake of saying it.

I do find Ca deficiency after I started dosing K2SO4. I that repeated the "experiment" and still find it consistent. When I dose K only (30ppm per week with water change) with Ca, I find Ca deficiency. When I do not dose K, I can last 2-3 of weeks without Ca added with no apparent problem until K deficiency set in. When I dose K again (30ppm per week with water change) without Ca, I am find Ca deficiency again. I need to supplement my tap water (GH 3) with about 4~5ppm Ca to get rid of the Ca deficiency.

That's why I have been asking the questions and no one have given me a convincing answer including those in the AB.

1. Is the increased K causing my plants to demand more Ca?

2. Or is the increased K blocking the Ca uptake?

BC

[PeterGwee]

Tom...could all this issue raise from the fact of inadequate CO2 levels? Ppl might be thinking that his CO2 is pretty well set but in fact it starts to drop to below optimal concentration as the plant uptake increases over time which many did not bother to look into?

[geoffrey]

Yeah Tom, I seem to have the same problem too. I lowered K from ~50ppm/week to 20ppm and my E. oriental is recovering. Otherwise it's new shoot would be pale white. Like BCLEE (so BC, you're slippery finger hi) said, could the excessive K leads to an increase in demand for Ca or another immobile nutrient in which we did not increase together with our increase in K?

[bclee]

----------------
On 5/2/2003 1:54:33 PM

Assume I have gH @ 20dKH and KH @ 6dKH. Since the illustration in the link uses ppm, I converted dKH into ppm by multiplying 17.8. (1dKH ~ 17.8ppm CaCO3). Right?
----------------

Correct. 1°dGH = 17.8ppm (CaCO3 equivilent)

----------------
Hence, 356ppm total hardness as CaCO3 and 107ppm carbonate hardness as CaCO3.
----------------

So far so good.

----------------
As shown, to get Mg concentration, we less 107ppm from 356ppm, giving us 249ppm Mg++ as CaCO3. Am I right so far?
----------------

WRONG!! KH just measure the alkalinity not CaCO3. If we assume the bulk of alkalinity comes from HCO3-/CO3--, KH just tell you how much HCO3-/CO3--, it does not give you any indication of how much Ca there is.

----------------
Now, converting Mg++ as CaCO3 to Mg++, I take 249ppm by 24.305 over 100.09 giving me 60ppm of Mg++. And as for Ca++, 107 x 40.09/100.09 = 42ppm of Ca++. So my tank has 60ppm of Mg and 42ppm of Ca, correct?
----------------

So the rest of the calculation is wrong.

----------------
1) Am I correct in the first place converting dKH to ppm for both gH and KH by just multiplying 17.8?
2) Is carbonate hardness also calcium hardness?
3) Since total hardness measures, bicarbonates, carbonates, sulphates etc, in the water, are our gH kit measuring that or only bicarbonates and carbonates?
----------------

1) Yes. But it is 17.8ppm of EQUIVALENT CaCO3 not actual CaCO3.

2) No.

3) Total hardness don't make sense to me. It is either KH or GH. KH kit measure the alkalinity which may be mainly carbonates. GH kit measure the divalent cations which usually are mainly Ca++ and Mg++.

BC

[geoffrey]

BC,

Okay, I understand that. Now what if I assume that the HCO3/CO3 radicals of corals are binded with Mg and Ca ions only, will the reading be a good guesstimate of Mg and Ca then?

[bclee]

Only when you can be sure that all the CO3 comes from CaCO3, you can know how much of CaCO3 by KH reading. But again, if there is other contributor like MgCO3 or NaHCO3, you would not be sure.

Even you know for certain that all KH comes from CaCO3, you cannot simply minus KH from GH and assume the rest is Mg. There can be salts like CaCl2, CaSO4, etc. (Cl- and SO4-- will not turn up in the KH.)

BC

[geoffrey]

Yes BC, there are other salts that contributes to total hardness, gH. I am also assuming that our gH kit is only measuring Mg++ and Ca++ from CO3, and no other stuffs. Basically, I don't need to have an exact reading of how much Mg or Ca I have, just a feel of how much there might be in the tank.

Conservatively, I further assume, until the actual composition of the coral used can be ascertain, it constitutes 10% of each element (coral should be loaded with more than 10% of Mg and Ca) than as a guide, I should roughly have Ca and Mg > 10% of 42ppm and 60ppm respectively. Yes, the method is flawed but do you think this estimates can be fairly reasonable?

[bclee]

Geoffrey, how do you know the ratio of Mg:Ca for coral chips?

BC

[geoffrey]

Oops, you got me there!! Damn, all the assumptions in vain.

[FC]

As far as my encounters go, K2SO4 does help to drive consumption rate of KNO3 and KH2PO4, not just NO3 and PO4. I mean, the extra K+ (from the K2SO4) on top of those from KNO3 and KH2PO4 does help. I encounter neither Ca nor Mg deficiency. It may be due to my coral chips and MgSO4 supplements.

Perhaps people who encounters Ca & Mg deficiency problem have probably overlooked the fact that NPK we add do drive up consumption of other macros. If we do not change enough water and/or frequent enough (like what Tom does), then Ca and Mg that came with the tap water would soon be depleted. This is especially true for people who live with low GH water.

To counter that, I add coral chips to keep GH above 4 and some Mg to go with. NPK in full dosage is limited to twice a week, mostly once.

If you ask me does high K+ of over 30~40ppm is necessary. I am sceptical; I usually keep the total at 20 as I am concerned about SO4 level.
If you ask me the addition of K2SO4 above KNO3 blocks Ca, I do not think so.

[freemann]

I had Ca deficiency with 13Dh and 5 Dh no change after I decreased hardness only other culprit could be Mg. I do 50 % water changes and all is within limits (hopefully) this is the current status of the deficiency:
http://www.bellybean.com/~pave/defic...deficiency.htm

[Plantbrain]

Well, I see nothing wrong with 10-20ppm of K+.
But I do have serious big beefs with the theory that K causes Ca inhibition.

I have Eustralis, Ammannia, Nesaea, Ludwigia etc with big fat stems, rapid growth, good color and I know these plants for many years.

I have lived in a number of different areas with differnt tap waters. Some very soft and some rock hard, more Ca than Marine systems even(440ppm). The plants responded fine, the ES seems to grow better with less Ca, K has no effect but ES is a funny plant anyway.

These plants mentioned do have have a common nutrient that will cause the noted effects, NO3. Which also is a tough nutrient to test for without good test kits.

It happens to me also when I let the NO3 go down to far. The plants are also very fast growers, especially after their roots start in on the Fe in the substrate.

CO2? Perhaps, stunted small growth is classic low CO2 levels but most of these folks tend to be good at this(hopefully).

But going down the nutrients working from CO2 down to the PO4/traces would help. I do large water changes to prevent anything from building up and also so I can dose regularly. This keeps good nutrient levels without so much reliance on test kits. Some of which have been wrong in the past(cheaper NO3 kits especially). So not everyone is going to buy a 60-80$USA test to measure something but about 6 of us in the Bay area did.

SF tap is damn near RO water from the Hetch Hetchy in the Sierras(beautiful Granite water shed, with a 400m raging waterfall you can stand right under and a 1000-1500m cliff faced valley 20 km long). Looks like Yosemite except without the crowds.

We used SeaChem's EQ which has lots of K, K2SO4, Baking soda, KNO3 and loads of traces.
Folks run their Ca levels low since they start off at 0.

We've done fine with nothing but K from the KNO3 and SeaChem EQ also. But I never found nor saw any K induced issues.

I also ask who really knows what Ca deficency looks like in each of their plants? Not corn, not strawberries but in each of these plants? This requires careful studies to do correctly.

There are a good deal of issues to consider before finding something that causes a problem.

I think it is better to see who has found something that DOES work and figure out why it's not working for YOU.
From that approach you will improve your growing skills. PO4 was long considered the cause of algae but I had lots of it and no algae.

Where was my algae? Did PO4 in fact cause algae?
We know better these days.

All it takes is for a few folks to say, well it's working for me.
So if this is true why don't I have problems?

In the meantime, try using less K+, 10-20ppm and see how you might improve the other parameters such as NO3, CO2, traces. That will help you and your plants no matter what you think

That's a win win approach I really suggest folks consider.

Regards,
Tom Barr