Problem with Riccia

[scottturnbull]

I have tested the water in the tank, tab water, which I use and the soda water. The results are as follows:
Tank water: KH 7
Tab water: KH 2
Soda water: KH 9

Those numbers aren't nearly as bad as I thought they might be. I was guessing the soda water would be about 12-15 dKH.

I supose this will affect the development of the plants, particularly the hemianthus. Also when I do water changes, this will be a stress for both plants and shrimps.

I don't know if the figures are extreme enough to affect the plants. The fish might suffer from osmotic shock, but that will only happen if you add too much soda water at once, or do a water change without adding any soda to the mix.

I'm still cautious about claiming there's no upper limit of kh for certain plants. Recently my eco-complete stopped leaching carbonates. A bolbitis heudelotii that was struggling suddenly went into overdrive. Beforehand it was dark green and crispy around the edges. Now it's translucent green and unfurling new leaves almost every day. The tropica website claims bolbitis prefers ph of 5-7. While the eco-complete was leaching carbonates, the ph was above 7 at night. Now it's stopped, the ph is below 7 all the time. This could be unrelated, though. I've tweaked everything else in between: CO2, flow, GH, dosing, you name it. So it's far from being a scientific observation.

 

[ceg4048]

Hi Ceg,

I thought you didn't beleive in testing water perameters? Is this your tank and if so how do you know the KH and GH values?

Hi sumink,
I don't believe in testing for nutrients. people testing for nutrients sends me into orbit. That behavior has a huge impact because plants require massive quantities of NPK so if the test kit lies to you and if you believe it then you get into trouble in a hurry. KH, GH and even pH test kits on the other hand are innocuous because there is not much inherent in their readings that can get you into trouble. You don't actually have to do anything with their results as the readings are academic. Ironically, that then makes them more or less useless from the perspective that you don't really need to worry about what they tell you from a plant's perspective. I don't use them very often, perhaps a couple times a year. KH/GH kits do show some consistency with TDS meters. The TDS meter tells you much more, especially if you are breeding softwater fish.

I'm still cautious about claiming there's no upper limit of kh for certain plants. Recently my eco-complete stopped leaching carbonates. A bolbitis heudelotii that was struggling suddenly went into overdrive. Beforehand it was dark green and crispy around the edges. Now it's translucent green and unfurling new leaves almost every day. The tropica website claims bolbitis prefers ph of 5-7. While the eco-complete was leaching carbonates, the ph was above 7 at night. Now it's stopped, the ph is below 7 all the time. This could be unrelated, though. I've tweaked everything else in between: CO2, flow, GH, dosing, you name it. So it's far from being a scientific observation.

Exactly. This is why one has to be able to stabilize all other variables and to vary one at a time, which is almost impossible in a tank. What you can do though is to now deliberately add carbonate to the tank to raise the KH to some target level and see what happens after about 3 weeks or so. Then, stop adding the additional carbonates and observe. Continue this cycle several times and observe results. If the bolbitis consistently exhibits negative reactions at or approaching the target level and consistently shows improved performance when the carbonates are removed and the KH is reduced then you'll have strong correlation between [high KH/high pH] and poor performance.

Some species such as Tonina and the verticillated versions of Ludwigia show strong general correlation between high KH/GH/TDS and poor performance but can still be grown well. It just means that when the water parameters are outside their supposedly optimal range one has less margin for error such that CO2 is more critical for example. If CO2/nutrients are kept high they can still perform well even outside the optimal range.

here is a typical example: This is Ludwigia inclinata var. verticillata "Cuba" which can sometimes be a difficult plant. It is purported to be KH/GH sensitive and is optimized for very soft water yet, has little or no trouble growing in the same hard water tank. CO2 and nutrient dosing are stringently adhered to however so there are few issues. This is one of the first plants in my tank to suffer if CO2 is at all sub-par. I'll need to determine whether it's sensitivity is as high in a low TDS tank. If I can show that performance and sensitivity is comparable then I'll strike this off the list of TDS sensitive plants and move it to the CO2 sensitive list.

Cheers

 

[spider72]

I'll need to determine whether it's sensitivity is as high in a low TDS tank. If I can show that performance and sensitivity is comparable then I'll strike this off the list of TDS sensitive plants and move it to the CO2 sensitive list.

Hi
My polish colleague is following this topic, he can read but probably his english is not good enough to write, anyway he would like to ask that somebody checked that cuba" is sensitive to KH/pH/TDS or is rather CO2 sensitive.
I've got "cuba" in my tank and only problem which I have is that plant is growing like a weed but I've got soft water 2dKH, 5-6dGH and a lot of CO2.
My colleague has harder water and he has some problems with this plant, but he is not sure is it a KH/pH problem or just CO2 deficiency. He is not sure about CO2 because other plants are doing well, but he realizes significance of CO2 and that plants are not equal in relation to CO2 saturation and stability levels required for each species.
So if anybody done some tests on this and want to share his thoughts that could be helpful.

 

[dw1305]

Hi all,
I don't think Riccia growth is inhibited by high KH, I've grown it in water saturated with calcium carbonate, to the extent that biogenic? calcium carbonate deposits appeared on some parts of the thallus. I've also seen it growing in water that had some maritime influence, so I don't think the sodium (Na) will bother it either. It has also been used as an experimental organism (in bio-accumulation/plant physiology studies) so there may well be some papers with it's actual tolerances published.

I think the chlorophyll deficient parts of the thallus in the photo looks like bleaching damage from a compound (quite possibly glutaraldehyde) rather than nutrient deficiency. I don't think that traditional nutrient deficiency symptoms tend to appear in Bryophytes (mosses and liverworts), although there is some evidence that chlorosis occurs in calcicolous ("lime loving") bryophytes, when they are grown in a low Ca environment.

Details here: http://www.bryoecol.mtu.edu/chapters/8-6NutrientDefic.pdf - "Bryophyte Ecology" Chap. 8 "Nutrients". More of the book here <http://www.bryoecol.mtu.edu/>.

cheers Darrel

 

[ceg4048]

...My colleague has harder water and he has some problems with this plant, but he is not sure is it a KH/pH problem or just CO2 deficiency. He is not sure about CO2 because other plants are doing well, but he realizes significance of CO2 and that plants are not equal in relation to CO2 saturation and stability levels required for each species.
So if anybody done some tests on this and want to share his thoughts that could be helpful.

Hi Maciek,
This is the essential problem unfortunately mate. No one wants to risk wrecking their hard work by testing. I haven't had the opportunity to grow L. Cuba in soft water yet. Your data is probably more valuable since you have soft water and probably do not have any flow or CO2 issues. Are you willing to lower the CO2 and check the response of individual specimens? Noooo...I'll bet.

Your colleague can also try a 3 week period using RO/DI water for his water changes only, and see what the effects are. If you each were to attack the issue from opposite directions you might resolve it more quickly.

FYI, I've found L. Pantanal to be even more difficult than L. Cuba in my hard water tank.
At some point I'll have a go with both of them in soft water. I regret that I don't have any data for you right now. Perhaps someone else has experience with these...


Cheers,

 

[spider72]

Hi guys
Darrel
I have ask specifically about cuba, but I presume your answer relates to topic title.
I have grown riccia in hard water with no problems as well, it is especially fast growing plant when floating on surface due to atmospheric CO2 access. Ricca was growing slower when tied to rock. If I am not mistaken riccia can't use carbonates so it probably requires higher CO2 level in water for good grow when submerged. And tanks for interesting reading, will have someting to read when laying in bed at night before sleep . Don't like read long articles on screen.

Clive
No, unfortunately I am not willing to lower CO2 level in my tank I have seen effects many times . But I can try to rise my KH, as I should still have potassium carbonate somwhere.
Anyway in this topic http://www.ukaps.org/forum/viewtopic.ph ... 24983de131 Tom shown picture of cuba growing in 18dKH water which can indicate that is more a CO2 problem. BTW my cuba looks much better than his .

 

[ceg4048]

No, unfortunately I am not willing to lower CO2 level in my tank I have seen effects many times . But I can try to rise my KH, as I should still have potassium carbonate somwhere.

How did I guess that correctly?
Yep, raising the kH is the next best thing, but it won't tell you if there is an equal sensitivity to poor CO2 at low kH.

Anyway in this topic http://www.ukaps.org/forum/viewtopic.ph ... 24983de131 Tom shown picture of cuba growing in 18dKH water which can indicate that is more a CO2 problem.

Yeah, but he also did mention that there is an issue with kH. I think it kind of corroborates what we talked about before, in that the margin of error is perhaps thinner under high kH...

BTW my cuba looks much better than his .

Hey no fair! The first sample shows cuba growing outside on the porch. The aquarium ones in the second photo look much nicer, no?

Cheers,

 

[spider72]

Yes, I know that there are species sensitive to higher KH (or higher pH caused by this higher KH) but just few of them.

My thougths on this in the past have been that this is related to form of carbon available which depends on pH (as per table below), and that at higher pH more CO2 is bound in carbonates.

But Tom's article about DIC mentioned that only about 1/400 of disolved CO2 will form H2CO3 which then will form HCO3- and CO3-2 depends on pH. If I understud this correctly than this should be insiginificant.
I tended to blame pH less, as in many shalow lakes with soft water and big amount of macrophyts, pH swing can be quite big, say from 5 to 9 pH in just few hours, according do Diana's book. But maybe pH sensitive plants are exclusive to rivers where such big pH swings don't exist. Just don't know.

God bless soft scotish water don't have this dilemma anymore, but I can say from my friends reports that is much easier keep all plants in softer water when dosing non limiting nutrients levels, so I belive there is some influece of pH (caused by KH) on CO2 availability to the plants or higher pH is affecting nutrients uptake somehow.

BTW my cuba looks much better than his .

Hey no fair! The first sample shows cuba growing outside on the porch. The aquarium ones in the second photo look much nicer, no?

I was just joking. Didn't you see the wink ?

 

[ceg4048]

Maciek,
There's something odd about the interpretation of that chart. I can't read the labels of the axes but this ought to be basically the same data we see for a dropchecker, i.e the pH/KH/CO2 relationship. The CO2/H2CO3 equilibrium constant is a function of the temperature/pressure of the water (and gas), not a function of the KH. At 25 DegC & Sea Level the number is something like 600 (the equations use the inverse of this, which is like 0.00166). What this means is that only 1/600th of the mass of dissolved CO2 actually converts to H2CO3. That means 599/600ths of it stays as CO2.

The way I look at that chart, if you have 3 cups of water, one with an equilibrium pH of 4, the second at 7 and the 3rd at pH 10 they will each have exactly the same amount of CO2 molecules dissolved in them. But the tail can't wag the dog here. I'll need to consider why the pH of first cup is at a pH of 4 and why the pH of the third cup is 10. Was the first cup driven to pH 4 by the injection of CO2? In fact were all three pH values arrived at by CO2 injection? If yes, was it the same amount of CO2 injection i.e the same amount of grams in each cup?

OK, lets say the answer is No. Let's say that I arrived at a pH of 4 by the addition of another acid in the cup of water and that the third cup was driven to pH 10 by the addition of a base. What this tells me is that in cup 1 the acids drive the equilibrium equation CO2 + H2O <=> H2CO3 to the left. But in cup 3 we have added a base so this drives the equation to the right. But a pH of 10 is completely off the chart and that's a lot of base to add. This means that a non-injected tank would have it's atmospheric dissolved CO2 completely converted to Bicarbonate/Carbonate.

We're not operating in either of those extreme regimes and on top of that we're injecting CO2. We're all operating somewhere between a pH 6-7 which means this chart would not apply.

OK, let's say the answer to the question is Yes. The pH values shown on the chart was driven by CO2 injection. Well there is no way at pH 7 that 80% of the dissolved gas is converted to Bicarbonate. That doesn't match the value given for the equilibrium constant.

This chart has got to be telling us something else. Could you help with the Polish mate?

Barr indicates that within our regime the solubility of CO2 is pretty much the same at any of our KH values. I didn't see any difference in terms of CO2 when I switched from soft water to hard water for the vast majority of the species. That's why I'm not really convinced that lower pH or lower KH makes any difference except for perhaps a few plants which are the subject of the discussion. There are just too many variables to draw that conclusion. And I'm talking about known difficult plants, A. reinikii, HC, Glosso, P. helferi - all grew better in high KH/higher pH than in low KH/lower pH water.

What I can't quantify is exactly how much more CO2 injection, if at all, did it take in the high KH tank to equal the growth performance compared to that of the low KH tank. I always try to point out that it's not even a good idea to compare tank performance at different years. I was a better plant grower by the time I decided to use tap water than when I was using soft water. So that has a tremendous effect of the comparison. Your L. cuba grows like a weed now because you are more aware of the importance of CO2/flow now than when you were using hard water. So that affects your results.

We really need to setup multiple tanks side by side and apply the growing principles equally across different water types to get good data. it's really the only way to determine the effects and the degree of effects.

Cheers,

 

[spider72]

Clive

Label on vertical axis can be translated as "percentage of disolved CO2 form in the solution".
Horizontal axis is just showing different solution pH: 4, 7 and 10 pH.

pH equilibrium in each solution has been achived by adding acid or base. CO2 concentration depends only on atmospheric gas diffiusion (no CO2 injection), so I presume there is the same CO2 concentration in each solution.

What I was going to confirm is fact that only small fraction of disolved CO2 will form H2CO3 and than HCO3- and CO3-2, which you confirmed. Tom stated in his article that this fraction is 1/400, but probably it is just aproximate figure and as you said depends on factors such as temperature, pressure of the water and gas. It does not really matter if this fraction is 1/400 or 1/600 but it does matter that this fraction is very small so it has not significant impact on CO2 availability even in hard water.
As I said before, I have been confused by this chart in the past and I have incorectly assumed that all CO2, even these injected, will be transformed to various forms according to this chart and the available CO2 forms will depend only on water pH. If this could be true than chart could indicate better CO2 availability at lower pH of water and suggest that soft water is better because of this pH.
But because this is not true and only rather inisignificantly small fraction of disolved CO2 will form carbonic acid and carbonates, than my friends most probably have plants problems (in general not these few KH/pH sensitive) not because of hard water and poorer CO2 availability but because they are simply dosing not enough gas.

 

[ceg4048]

Exactly mate, that's what none of these charts ever mention, that it only applies to that small fraction that forms carbonic acid. The other thing worth noting is that the equilibrium reactions are very slow. That's the reason the dropchecker is only ever indicating what the value was a few hours ago.

I agree that your colleague's issues is much more likely to be a matter of injection rate/flow/distribution, although I'd still like to do a comparison of these verticillated Ludwigias in high/low KH water.

Cheers,

 

[spider72]

I've got only cuba in my tank, but I have added yesterday K2CO3 to rise KH about 2dKH, will rise KH today next 2dKH. My target is to achive about 10dKH in few days (don't want stress the fish rising KH from 2-3 to 10 in one day) and keep it for 2-3 weeks or maybe longer, depends on observations.

 

[ceg4048]

Cool. Will be interesting to see the results.

Cheers,