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Old 11-29-2007, 03:49 AM   #1 (permalink)
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Default Once more about soft vs. hard water and Ca:Mg ratios

There were many talks over soft/hard water issues so it may seem another one is unnecessary. However, over the

past few months i carried out some experiments on the subject to "uncover the truth". Before i set up my first

planted tank i was often told that one must use soft water. Obviously the word "soft" may be somewhatconfusing:

for some folks it may be GH = 6, for other it may be GH = 3.
So, my first tank was filled with water of GH = 6..7. The water was prepared by mixing some RO water with tap

one. I didn't know what levels of Ca & Mg were in the tank. I used commercial micro and macro ferts. Most

commercial macro ferts usually have very low nitrogen concentrations. By using this macro fert i obtained very

low NO3 and PO4 levels - usually below 5 ppm (sometimes it was unmeasurable). PO4 was typically 0.1 ppm. Under

such conditions the results were as follows:

Case 1.

- most plants grew well (Glossostigma, Umbrosum, Alternatara, Polysperma)
- such species as Cabomba were stunted due to low NO3 (they love high NO3)
- GDA appeared on the glass very often
- BBA grew on many stem plants, driftwood, heaters and on the rear glass
- heavy BGA algae outbreaks occured a few times
- no stunted tips
- rich plants colors
- poor pearling


Three months after setting up my first tank i was advised to use only RO water
reconstituted by a commercial mixture very similar to that of Seachem "Equilibrium". It was the only change i

made (macro dosage wasn't altered - i used the same doses of K, PO4 and N which was in the form of NH4). The

tests showed GH = 2, KH = 1. (laboratory tests were made showing Ca = 8, Mg = 4). PO4 and NO3 were low again

(0.1, 3 ppm respectively). The results were as follows:

Case 2.

- very good and fast plants growth, massive prunings were required every week
- cabombas vere still stunted
- no stunted tips but some Rotala Indica tips were "bald" due to low Ca
- GDA appeared only when there were unmeasurable PO4 and low K doses (no more than 1 ppm a day)
- BBA slowly dissapeared
- rich plants colors
- hard water-loving Cryptocoryne species rot and died
- moderate pearling


Then i got to know about EI method. I added KNO3 and KH2PO4. NO3 rose to 10..15 ppm, PO4 to 1 ppm. Such levels in

very soft water (GH = 2) i had caused the following:

Case 3.

- exceptionally good growth of Cabomba and Blyxa Japonica (Cabomba had to be pruned twice a week)
- a bit faster growth of Didiplis Diandra
- almost all growing tips on Rotalas, Umbrosum, polysperma were stunted
- alternateras had horribly deformed and bent leaves, some specimens just died quickly
- leaves colors not affected by higher NO3
- very heavy pearling
- some plants didn't show any changes in growth and coloration; these inlcuded Glossistigma, Anubias


As you may have read in my previous threads and posts the next steps i made was struggling with stunted tips and leaves deformations; finally it turned out that the issues were caused by low K and high NO3 (and sometimes low Mg) (i always thought it was due to low Ca but adding high amounts of Ca (50 ppm) didn't help at all). However, a few weeks ago i switched to what i've described in Case 2: low GH (it is 3 this time...), very low NO3, very low PO4, high K. Now myt plants show quite good growth, no stunting, no deformations, no problems with algae. It also seems that when using very soft water it should also be low in chlorides, sulphates and sodium - i get the impression they contribute to stunting when they are present in high concentrations. Approximately Cl is below 2 ppm, Na below 5, SO4 comes from MgSO4 and it is about 16 ppm.

Ca:Mg ratio Considerations

It is often said what Ca:Mg ratio we should keep in our tanks. Most sources say about 3:1..4:1.
It seems most of us (if it's possible) attempt to maintain 4:1 ratio thinking it's the best solution to many problems (especially connected with Ca deficiency issues). I can truly say that Ca:Mg which should be kept depends on a few things. When i first discovered that most of my issues with stunting were caused by inadequate K doses i tried to keep K high (usually 30 ppm). It usuallly worked fine for about 2 months but after this time i noticed that many young new leaves became pale and growth was poor. Most plants looked as if they were iron starved so i added high iron doses ending up with over 0.5 ppm Fe in the water column. Such high level of Fe didn't improve anything. I also increased maganese dosage (Mn deficiency may resemble Fe deficiency in some cases) but it was all in vain. Finally i added Mg (Mg was increased from 5 to 10 ppm). In three days i noticed faster growth and pale colors dissapeared within a week. The Ca:Mg ratio at which the improvement was noticed was 2:1.
Such a ratio may induce Ca deficiency (some people on the forum experienced that after adding more Mg) but it seems to me it happens mainly in hard water. When i had 2:1 ratio the only plant that was affected was Cardamine Lyrata. Its leaves were curled upward which was a clear sign of Mg excess but the plant got used to 2:1 radio within a month and the curling declined. In turn, in soft water (GH 2..3) which i use now 2:1 ratio works very well; i don't experience any problems with Ca deficiency or Mg excess. Another thing worth mentioning is what Mg deficiency looks like in aquatic environment. Most articles and literature connected with terrestial plants say, Mg defficiency appears as yellowing on lower leaves. I can say that in many cases it's not true in planted tanks. As i have written above i experienced Mg deficiency that appeared as yellowing on young leaves.
It's often confused with Fe deficiency. If you see something like this, and if you dose high levels of Fe it may be a clear sign that Mg is deficient (unless your current Ca:Mg ratio is 2:1 - in this case pale colors on young leaves may be a result of micro overfertizing). Also, it's not always true K excess causes Mg deficiency. Currently i dose only 4 ppm of Mg to changed water every week and add 2 ppm of K every day and i can't see any signs of Mg deficiency (this routine has been repeated for over a month now)


To Summarize:

1. If you use hard tap water you can dose higher NO3, PO4
2. If you have soft water dose little NO3 and PO4; in many cases with very soft water no NO3 dosing is needed
3. Don't be afraid of high K - in all cases it should be high (20..30 ppm or more)
4. Avoid using fertilizers high in boron; i noticed it's the most toxic element causing slow growth and chlorosis
(however, in some cases high boron levels work fine but i don't know why it happens)
5. Don't be fooled by some Amano tanks where he uses extremely soft water ( for example, GH = 1). I think his tanks have Power Sand substrate enriched with CaCO3.
6. I suppose high N may be used in soft water tanks but only when it's injected under the roots.
7. Hard water is a paradise for snails - you will have to remove 50 or more snails from your tank
every day (unless you use a chemical agent to kill them once and for all but it will also can destroy your plants)

p.s. sorry for such long text... but i believe the hobby requires me to share my experiences (even though T.Barr or T.Amano would deny everything...)
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Old 11-29-2007, 08:03 AM   #2 (permalink)
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Quote:
Originally Posted by kekon View Post
very soft water (GH = 2) i had caused the following:

Case 3.

- exceptionally good growth of Cabomba and Blyxa Japonica (Cabomba had to be pruned twice a week)
- a bit faster growth of Didiplis Diandra
- almost all growing tips on Rotalas, Umbrosum, polysperma were stunted
- alternateras had horribly deformed and bent leaves, some specimens just died quickly
- leaves colors not affected by higher NO3
- very heavy pearling
- some plants didn't show any changes in growth and coloration; these inlcuded Glossistigma, Anubias
This describes my tank very well. My tap water here is pretty much gH <1 kH <1. I boost gH to 3 using a home made booster very much like Seachem's Equilibrium and with a Ca:Mg ration of 4:1 and a fair bit of K.

Blyxa and Limnophila grow explosively as does Hygrophila corymbosa 'kompact' but I struggle with stunted growth in most of my Rotala (R. mexicana, R. occultiflora, R. rotundifolia). R. macranda grows OK. Hygrophila polysperma also shows some stunting. I also notice that many plants in my tank tend to a greener colour despite being under metal halide lights. I have a narrow Echinodorus tenellus that many people grow as a nice pink/red, yet mine is mostly green. H. polysperma 'rosanervig' gorws green under the halides in this tank yet its a beautiful pink under a much lower wattage T8 flouro in another tank.

Based on your observations - I'm going to try increasing Mg for a bit and see if my Rotalas respond.
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Old 12-01-2007, 08:09 AM   #3 (permalink)
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Thanks for the interesting info!

I've always felt that hard water (more specifically water with high KH) requires higher dosing of ferts to avoid deficiencies. Also I recommend avoiding the use of gluconate as an iron chelator as I don't think it works well with high KH.

I've also found that in high KH water, BBA is very difficult to avoid, even with adequate CO2 levels and good ferts.

Last edited by Laith; 12-06-2007 at 09:11 AM..
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Old 12-02-2007, 02:01 AM   #4 (permalink)
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Quote:
Originally Posted by kekon View Post
I It usually worked fine for about 2 months but after this time i noticed that many young new leaves became pale and growth was poor. Most plants looked as if they were iron starved so i added high iron doses ending up with over 0.5 ppm Fe in the water column. Such high level of Fe didn't improve anything. I also increased manganese dosage (Mn deficiency may resemble Fe deficiency in some cases) but it was all in vain.
Most articles and literature connected with terrestrial plants say, Mg deficiency appears as yellowing on lower leaves. I can say that in many cases it's not true in planted tanks. As i have written above i experienced Mg deficiency that appeared as yellowing on young leaves.
It's often confused with Fe deficiency.
You are absolutely right! I've passed through everything you describe above, especially with pale Anubias leaf when high light exposed. Congratulation for your such in depth research for this problem. It was very useful for me and probably for others too!
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Old 12-02-2007, 02:34 AM   #5 (permalink)
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Quote:
Originally Posted by kekon View Post
...yellowing on young leaves.It's often confused with Fe deficiency. If you see something like this, and if you dose high levels of Fe it may be a clear sign that Mg is deficient (unless your current Ca:Mg ratio is 2:1 - in this case pale colors on young leaves may be a result of micro overfertizing)....)

Too much micros can lead to pale colored young leaves? That's an interesting statement! Is it just an assumption or did you really observe something like that?

May I also ask you about your experiences with silicates? Did you ever have problems with Si02 in the past (other than growth of diatoms during the initial stages of a new tank)? Do you know how much silicates your tank water and the water you use for wc's holds?


You have done an amazing amount of work. Thank you for your comprehensive summary!

Best regards,
Detlef

Last edited by detlef; 12-02-2007 at 06:29 AM..
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Old 12-04-2007, 02:25 PM   #6 (permalink)
 
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

I knew that Kekon was preparing something in the background. Always interesting and informative, I follow your threads with attention, thanks for your work!

I just want to share an experiment I realize with my thread ... Survey of 33 gal on 32 weeks... 11x17 inches, 528k, pdf...
Link at : http://www.grafcomm.ca/33gal.pdf

This survey of water parameters on 33 weeks is compare to the general health of plants in this 33 gal tank.
— Anubias nana
— Crypt
— Elodea
— Ludwigia repens
— Rotala indica
— Small sword plants
— Sagitaria
I’m still looking at this compilation and probably come with some conclusion later, or maybe some of you out there can share what they think....

Anyway, I just did an average of the concentration of nutrients in the 9 weeks where the plants look there best.
It should give an idea of the optimum concentration for this particular setup.

PH= 6.83
KH = 18.2 mg/l
GH = 148 mg/l
Ca = 45.5 mg/l
Mg = 12 mg/l
NO3 = 7.1 mg/l
P04 = .7 mg/l
K = 16.5 mg/l add every week
Fe = .33 mg/l

Personally I think that a level of Ca between 40 to 60 mg/l are OK
Surprisingly it seem that the ratio between Mg and Ca do not seem to be the only culprit in Ca absorption. Anyway I beleive that the Mg level itself is more important that the ratio of Ca/mg

My main concern was to obtain fast growing plants like Elodea and Rotala to thrive and the Ludwigia to not be crinkled and grow reasonably fast ( 2 to 3 inches a week)
The Ludwigia problem seems to be somekind of Ca absorption limitation.

Last edited by Glouglou; 12-04-2007 at 03:17 PM..
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Old 12-05-2007, 04:59 AM   #7 (permalink)
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Wow, the chart is very interesting ! I will print it and watch thoroughly ! I've never collected information about my plants in such a form... I see the chart contains the values at witch my "favourite" problem occured - tip burn

Quote:
PH= 6.83
KH = 18.2 mg/l
GH = 148 mg/l
Ca = 45.5 mg/l
Mg = 12 mg/l
NO3 = 7.1 mg/l
P04 = .7 mg/l
K = 16.5 mg/l add every week
Fe = .33 mg/l

I had similar values in my tank and it was not bad; the only problem were snails (they love Ca & Mg)
NO3 was close to 5 ppm (above this value some plants were stunted and had burned tips)


Quote:
Too much micros can lead to pale colored young leaves? That's an interesting statement! Is it just an assumption or did you really observe something like that?
I did observe such effects on my plants and so did some people who experimented with it. It is known that the more micros one adds the more colorful plants become but there is some sticking point with that. Beyond this point leaves will turn pale. I'm not able to give exact maximum concentration of each micronutrient because i don't have an access to a laboratory which is capable of measuring micronutrients in the water but i can frankly say that the main critical element is boron. Together with my friend we experimented with boron and it turned out that adding more than 0.02 ppm of boron weekly (500% TMG dose) ends up with stopped growth and yellowing. However, most people use good fertilizers (TMG, ADA, Flourish etc.) which are unlikely to cause any micro excess (provided they're not overdosed). The problem may occur in some tanks where PMDD fert is used which has high boron content. The second element which can cause pale colors is copper. It can cause Fe deficiency but one should not be afraid of high Cu content in TMG because it is still to liitle to cause Fe deficiency (i noticed some plants like Didiplis Diandra for example, like more Cu - it has richer red colors)

Quote:
May I also ask you about your experiences with silicates? Did you ever have problems with Si02 in the past (other than growth of diatoms during the initial stages of a new tank)? Do you know how much silicates your tank water and the water you use for wc's holds?
Unfortunately my experiments with silicates failed... I wanted to add Si artifically to the tank but the problem was with finding any soluble Si compound. The only ones i found were Na2SiO3 and K2SIO3 (sodium silicate and potassium silicate) but i didn't add them to the tank because the salts are strong base wchich could end up with high pH rise (i was very afraid of doing it...). As far as silicates in the wc's water are concerned i found some info. Typical concentrations are 10..50 ppm of SiO2 (however this is very general info; it depends of the source where water is taken and suppied to our houses) Some people say silicates contribute to BBA algae but none of them was able to tell me what levels of SiO2 are harmful.
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Old 12-05-2007, 02:26 PM   #8 (permalink)
 
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Well that obvious Ca , uptake, deficiency problem is one that I really want to takle.

This some info I collect around:
Quote:
Calcium:
This element is found in its ionic form (Ca++) in the soil solution and in a hydroponic nutrient solution. This is also the form that the plant can absorb. Acidification of the nutrient solution when using soilless mixes can cause a slight reduction in the availability of calcium to the plant.

In sumerged plants:
Uptake reducing rapidly under 6.5 ph

Overall function:
In the cell, calcium can combine with bicarbonate to form the base, calcium bicarbonate, that is an effective neutralizing agent for acids formed during cellular metabolism.


Calcium uptake mechanism. (submerged plants)
Both Ca and Mg in land plants do not 'move' as readily in the xylem as other ions. The hypothesis is that because the movement of water through aquatic plants is less than in land plants, Mg requirements can't be satisfied by upward movement. At no time have I said that Ca and Mg can't move within the xylem of aquatic plants ... in fact experimental evidence clearly shows that at least Ca can move up or down in aquatic plants tissues (just not at a rapid enough rate to satisfy external requirements).

Calcium uptake mechanism. (Land plants)
Calcium uptake is by mass flow. Calcium contained in the soil solution moves into the root system with the influx of water and is carried in the transpiration stream to the various plant organs. Usually those areas with the greatest activity receive more water and therefore more calcium. Mass flow delivers more calcium than plants take up. Calcium uptake is generally genetically controlled. One of the restrictions is the fact that only newly expanding unsuberized root caps can absorb calcium. Any environmental factor that limits root expansion limits the uptake of calcium predisposing plants to physiological disorders.

Calcium and Nitrogen
Nitrate nitrogen tends to accumulate in the leaves and increase organic acid production, which increases the demand for Calcium to neutralize the acidity, if this calcium is in short supply calcium may be mobilized from the roots. This movement of calcium from roots is the demise of the root integrity and can lead to leaky roots and ethylene production signaling the plant to shut down.

In land Plants:
Problem with calcium uptake seems to be induced by factors that tend to limit the timely uptake or distribution of calcium within the plant. There are a number of factors that can contribute to this condition.

A low pH (6.0) or a high magnesium content can contribute to calcium deficiency.

[B]Natural water have a ratio of around 4:3 (to verify)[B]

With a ratio greater than about 5:11 of calcium to magnesium it may be of some benefit to add calcium even if you don't need to adjust your pH. Gypsum (calcium sulfate) is high in calcium but won't affect the pH. The best ph is 6.5 to 6.8
You can add calcium with Calcium sulfate or Calcium chloride

If your soil does not have either a low pH or a high magnesium content, over-fertilizing with potassium or nitrogen can influence the amount and distribution of calcium.

Last edited by Glouglou; 12-05-2007 at 04:38 PM..
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Old 12-05-2007, 06:02 PM   #9 (permalink)
 
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

I don’t think that we can’t find any magic formula or ideal ratio for nutrients. To much parameters are to consider from, Ph, light, CO2, water movement, interaction of nutrients, type of plants etc..

But we probably can lay down some guide line that will procured some satisfaction...

As Ca is involve, I can propose some ideas (only for low Kh, low Gh, acidic setup)...

• Ca is really immobile as a nutrient and one of the lower luxury uptake capacity (with magnesium)
Content in plant by dry weight: Ca=650 mg/kg
Magnesium: 210mg/kg
Ratio: +- (Ca) 3:1 (Mg)
If we transfer this in ratio in dissolution in water. With 40 mg/l Ca we have around 13mg/l.

• All alkalis have an effect on each other, to much of one will suppress the other
In order or influence we can put K in first (but Definitively PH seem to be the most influential external factor)
it appears that the reduction in Ca2+ absorption is closely associated with the increasing uptake of K+

Some study...
Quote:
The uptake of potassium, calcium, and magnesium ions by maize and the interrelationships among the cations have been investigated at 48 K: Ca: Mg ratios in culture solutions. Calcium was found to stimulate K+ and Mg++ uptake at certain cation ratios but inhibit it at others. Potassium did the same for Ca++ uptake, and Mg++ for Ca++ and K+. The uptake of Mg++ was generally enhanced by K+. The sum of the cations in the plants expressed in meq was fairly constant for treatments of the same K+ concentration at the low to moderate levels of K+, but at considerably higher (> 24 meq l–1) K+ levels the constancy was not dependent on K+ concentration. Potassium depressed, but Mg++ stimulated phosphorus accumulation. Calcium stimulated phosphate absorption at certain cation ratios but had no effect at others. The plant yield increased with increasing K+ up to 24 meq l–1 of K+ after which the yield tended to fall with further increase in K+. The yield was also increased by Ca++. Magnesium increased the yield at certain cation ratios and either depressed it or was without effect at others.
1— Definitively PH is important. Under 6.5 the Ca uptake will go rapidly down. 6.8 will be probably an ideal target when all the nutrients uptake are considerate. As is role in the cell as an acid neutralizing agent in conjunction with bicarbonate we can see that low PH, low kh setup have nothing to help the situation.

2— Enough Ca is needed in dissolution in the water, perhaps (if you look at my survey) between 40 to 60 mg/l should be right. But a little bit of Ca in the soil will probably a little help, if we have a healthy root system.

3 — Magnesium is needed , perhaps a ratio slightly higher on the magnesium side that the normally 4:1. Personally I will go around (Ca) 3: 1 (Mg) ex: 40mg/l for 13 mg/l (Kekon even say 2:1 work)

4 — Potassium is needed, 20 to 30 mg/l, as you say, Kekon seem alright for me. The only problem with k is to measure what we have and what is used. Try and error can apply, personally I will add around 16mg/l every week based on my survey and see.

5 — To much nitrate will be probably detrimental to Calcium uptake. Nitrogen tends to accumulate in the leaves and increase organic acid production, which increases the demand for Calcium to neutralize the acidity, if this calcium is in short supply calcium may be mobilized from the roots. This movement of calcium from roots is the demise of the root integrity and can lead to leaky roots and ethylene production signaling the plant to shut down in land plants. In submerged plants, I believe that nitrogen will have the same effect directly at the leave structure, taking away calcium for an healthy growth

Boron have a sweet spot in correlation with Ca, but I will play with that at last resort.
In my case I remember give an small overdose of boron in my survey, I have to look at my note what week it was...

Last edited by Glouglou; 12-06-2007 at 01:45 PM..
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Old 12-05-2007, 10:20 PM   #10 (permalink)
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Default Re: Once more about soft vs. hard water and Ca:Mg ratios

Good stuff guys. To put this to practical use, is there anyone that can comment on how this information might affect people's success with typical EI dosing? What I'm getting at is that EI seems to work marvelously for certain people and not at all for others. Are there water parameters that work well with EI methods? What situations might require dosing modifications?
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