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Choosing Aquarium Plants For Soft And/Or Hard Water

Hi @jameson_uk

You can see an analysis of your tap water if you download a full water quality report from your water company's web site. Well worth doing. It will show you figures for calcium, magnesium and a whole lot more. I see that you are in Birmingham so you possibly get your water from Severn Trent. Just go to their site and follow the links. Easy peasy! It would be very interesting to know what your calcium and magnesium figures are.

JPC

I’m in the Severn Trent region, and unfortunately they don’t seem to list a number for Magnesium content, just general hardness - unless it’s listed under a name I don’t recognise (I’m no chemist!).

This is the page where a post code can be entered.

https://www.stwater.co.uk/my-supply/water-quality/check-my-water-quality/
 
Thanks, couldn't find it on my phone.
I found the average hardness stats which for my area state

Alkalinity (Average HCO3 mg/l) - 132
Calcium (Average Ca mg/l) - 54
Magnesium (Average Mg mg/l) - 9.68
Total hardness (average) - CaCO3 mg/l -
Total hardness (average) - Degrees (German) - 9.8

Although my hardness is slightly higher than that and I possibly get water from a neighbouring zone as I live on the border but it is in the right ball park I think.
 
I’m in the Severn Trent region, and unfortunately they don’t seem to list a number for Magnesium content, just general hardness - unless it’s listed under a name I don’t recognise (I’m no chemist!).

This is the page where a post code can be entered.

https://www.stwater.co.uk/my-supply/water-quality/check-my-water-quality/

Hi @Wookii

Obviously, I can't try the link as I don't live in your neck of the woods so don't have a valid post code. There should be an option to see a full water quality report. Magnesium will almost certainly be listed as its full name - magnesium - as opposed to Mg.

JPC
 
I’m in the Severn Trent region, and unfortunately they don’t seem to list a number for Magnesium content, just general hardness - unless it’s listed under a name I don’t recognise (I’m no chemist!).

This is the page where a post code can be entered.

https://www.stwater.co.uk/my-supply/water-quality/check-my-water-quality/

Hi @Wookii

Obviously, I can't try the link as I don't live in your neck of the woods so don't have a valid post code. There should be an option to see a full water quality report. Magnesium will almost certainly be listed as its full name - magnesium - as opposed to Mg.

JPC
 
Hi all,
I’m in the Severn Trent region, and unfortunately they don’t seem to list a number for Magnesium content,
They aren't obliged to report parameters where there isn't a legal limit. This means that for some of the parameters we are interested in (magnesium, phosphorus etc) levels aren't necessarily reported.

Because you are in Nottingham you may have appreciable levels of magnesium in your water for <"geological reasons">. This is the extent of the magnesian limestone deposit and and aquifer.


MagnesianLimestone.png


cheers Darrel
 
Hi @Wookii

Obviously, I can't try the link as I don't live in your neck of the woods so don't have a valid post code. There should be an option to see a full water quality report. Magnesium will almost certainly be listed as its full name - magnesium - as opposed to Mg.

JPC
The actual water quality report for my area has everything like Boron, Manganese, copper, iron... But not magnesium. The figures above are from a second water hardness report I came across.
 
Hi @Wookii

Obviously, I can't try the link as I don't live in your neck of the woods so don't have a valid post code. There should be an option to see a full water quality report. Magnesium will almost certainly be listed as its full name - magnesium - as opposed to Mg.

JPC

Try this: NG9 6QX (a local Tesco as I obviously don’t want to add my personal postcode on a public forum)
 
Hi all,They aren't obliged to report parameters where there isn't a legal limit. This means that for some of the parameters we are interested in (magnesium, phosphorus etc) levels aren't necessarily reported.

Because you are in Nottingham you may have appreciable levels of magnesium in your water for <"geological reasons">. This is the extent of the magnesian limestone deposit and and aquifer.


MagnesianLimestone.png


cheers Darrel

Thanks Darrel. Yes I do think there is a fair amount in the tap water. I know you don’t like test kits, but when I have used one for Mg the resulting reading is in the upper range of colour values.
 
The actual water quality report for my area has everything like Boron, Manganese, copper, iron... But not magnesium. The figures above are from a second water hardness report I came across.

If you are Severn Trent too, I assume you’re seeing the same report as me.

Where did you get the additional water hardness report?
 
If you are Severn Trent too, I assume you’re seeing the same report as me.
As above, my water comes from South Staffs not Severn Trent (I near enough live in Lichfield not Birmingham).
Looks like Severn Trent just give you the hardness and not a breakdown. I might be tempted to email them and ask if they can provide you with a breakdown as I suspect they have probably measured it.
 
Hi all,
I might be tempted to email them and ask if they can provide you with a breakdown as I suspect they have probably measured it.
They may do if they use ICP for the analysis, it simultaneously gives you a reading for all the metal ions. The advantage of this is that you don't need to shuffle through the lamps for one with an <"appropriate wavelength"> to find the emission spectra specifically for magnesium.

cheers Darrel
 
Hi Folks,

I have just been reading a bit more of Diana Walstad's book, Ecology of the Planted Aquarium. There is a section in which she discusses hardwater natural habitats and the hardwater nutrients that are in plentiful supply in these habitats. Regarding Amazon Swordplants, she makes the comment that "They don't do well in tanks with softwater..." QED. I think that says it all.

JPC
 
I think Diana Walstad lists plants that can use bicarbonate as a carbon source? In that case they should all do well in harder water, if they can't they are more likely to struggle.
Diana Walstad (1) is no scientist and does not follow rules of scientific ethics, (2) her book is rather outdated and she never cared to study later literature because, in fact, she moved to a quite different field of interest.
So, as for her list: Even at the time she has been writing her book there was growing consensus that submerged plants are not divided into two groups - can and can not - but rather there's a continuous scale of varying affinity of species to bicarbonates.
V. spiralis is a plant on which Diana Walstad carried out an experiment. This plant was shown to distinctly dislike acidic soft water!
Yep. This is a perfect example of her low honesty. She performed the experiment at two values of pH: 8 and 4 (four!). Only very few plants can live in such strongly acidic water. Yet that does not mean that V. spiralis cannot thrive at pH 6. She didn't try, but felt free to conclude that not only V. spiralis, but majority of all water plants prefer alkaline water. She arranged this "scientific" experiment in such a way to 'prove' her thesis.

In another place she concludes that water hardness is THE decisive factor. Mind you, water hardness is mostly an industrially important number. Calcium and magnesium are important for all waterworks because their compounds tend to precipitate in plumbings. But from plants' point of view, there's no reason to see Ca & Mg as more important than, say, potassium or sulfur.
Of variables which generally and profoundly affect living conditions for plants, two (interconnected) stand clearly atop: pH and bicarbonate content (rather than alkalinity).
the plants are showing clear signs of iron induced chlorosis, and I would take that as a pretty good indication that Rotala rotundifolia is much happier in softer water.
Again, it's not soft water (low GH) but pH and bicarbonates which strongly affect iron availability.
some plants may do better in hard water because they can synthesise carbon from bicarbonates
All higher plants prefer CO2 over HCO3-, without exemptions. But those with higher affinity for bicarbonates are in a competitive advantage at higher pH.
I usually ignore other folks/experts opinions and try it anyway. Half the time they're just plain wrong or have confused cause and effect. I've lost count of the times plants have thrived or died when and where they "shouldn't" have.
Unfortunately, you're right. Most guides are fairly useless. I like Flowgrow database. But it also features many disputable suggestions, and even outright nonsenses. I mean, they often combine recommendations for pH and KH in such a way that if you tried to follow it to the letter, you'd have to inject hundreds of mg CO2 per litre. By the way, just a few days ago I asked them about it and they were pretty rude to me.
Where can I get a list of aquarium plants that includes recommended water hardness?
As far as I know, nowhere.
I think it's due to prevailing habit of CO2 injection and using strong artificial chelates. When you read the guides (par example Flowgrow), it's basically the same for any species. "A LOT" approach - a lot of light, a lot of CO2, a lot of macronutrients, a lot of micronutrients, and if the plant happens to possess rich roots, they usually recomment nutrient-rich substrate (which is a clearly mistaken reasoning).
With CO2 injection and strong artificial chelates you can overcome many difficulties stemming from natural preferences of a given species. So, recommendations made by people who run hi-tech tanks are mostly worthless - they don't refer to standard (natural) conditions.
That's why I've been performing my experiments, strictly without CO2 and artificial chelates, and in this way I've been collecting data on what our plants truly like & hate. An endless source of fun and enlightenment. I've published some articles on my findings, unfortunately, in my native language only. It's too difficult for me to translate them to English. Besides, I think the original publisher has some rights to them, perhaps I can't publish them elsewhere without consent. Never asked, anyway...
 
Yet that does not mean that V. spiralis cannot thrive at pH 6.
V spiralis grows like a weed in my tank, lovely soft water with a ph around 6. So agree Diana is completely wrong on this assumption.

With CO2 injection and strong artificial chelates you can overcome many difficulties stemming from natural preferences of a given species. So, recommendations made by people who run hi-tech tanks are mostly worthless
Scratch that, vallisneria will only grow in hard water. 😆
 
Hi all,
Again, it's not soft water (low GH) but pH and bicarbonates which strongly affect iron availability.
That is a bit of sloppiness on my behalf really. I've used "hard" and "soft" to refer to the calcium carbonate (CaCO3) of the water, and I haven't differentiated between <"permanent hardness"> (dGH or divalent cations) and temporary hardness (dKH or carbonate content, <"measured as alkalinity">).

I've done this because, <"in the UK">, nearly all of <"our aquifers are limestone">, and that <"supplies 1 dGH : 1 dKH">. You can actually go further than that and say, for most of us, our hard water is ~ 17 dGH, 17 dKH & pH~8, because of the <"carbonate ~ CO2 ~ pH equilibrium">.

If you use RO you can decouple dGH and dKH, which is what both @james C <"James' Planted Tank - Re-mineralising RO Water"> and @Roland have done. <"Soft water tank">.
there was growing consensus that submerged plants are not divided into two groups - can and can not - but rather there's a continuous scale of varying affinity of species to bicarbonates.
Definitely will be, it is back to ecology and <"shades of grey">. Having said that some plants are going to occur in situations where the water can be hard or soft, but there are plants that are, very much, restricted to soft or hard water. If you just look at the "Pondweeds" (genus Potamogeton) in N. Europe, if you find Bog Pondweed (Potamogeton polygonifolius), you are <"in a peat bog"> and if you find Fennel-leaved Ponweed (Potamogeton pectinatus) you have <"nutrient & base rich water">.
She didn't try, but felt free to conclude that not only V. spiralis, but majority of all water plants prefer alkaline water.
I would agree that there are bits of the <"Ecology of the Planted Aquarium"> that aren't entirely objective. In some ways that was the answer she wanted, because she had to have aquariums with base rich, alkaline conditions. This was because she didn't change any water and therefore didn't replenish the <"carbonate hardness consumed during microbial nitrification">. I'd cut her a <"bit more slack than you do">, particularly as she <"revised some her practices"> after she had written the book.
Most guides are fairly useless. I like Flowgrow database. But it also features many disputable suggestions, and even outright nonsenses. I mean, they often combine recommendations for pH and KH in such a way that if you tried to follow it to the letter, you'd have to inject hundreds of mg CO2 per litre
Again I'd cut them a bit more slack as well. There are new "aquatic plants" appearing all the time. I'll be honest, personally I have much more of an issue with some of the plants sold as "aquatic", <"when they patently aren't">.

cheers Darrel
 
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Again, it's not soft water (low GH) but pH and bicarbonates
I've used "hard" and "soft" to refer to the calcium carbonate (CaCO3) of the water

I have always worked under the assumption that the softness/hardness of water related exclusively to the carbonate levels (so KH and ultimately pH) in the water, is this not correct? Do the magnesium and calcium levels come into play when detemining the hardness of water also?

For example I would have assumed water with KH0 / GH10 would be soft, but water with KH10, GH0 would be hard?
 
Hi all,
I have always worked under the assumption that the softness/hardness of water related exclusively to the carbonate levels (so KH and ultimately pH) in the water, is this not correct? Do the magnesium and calcium levels come into play when detemining the hardness of water also?
It is back to definitions, so I've used it that context, but @_Maq_ has used "hardness" to purely refer to the dGH, the <"permanent hardness">. Rather than referring to the dKH ("temporary hardness") as "hardness" the term "alkalinity" is preferred, because that is what we actually measure.

I can see the rationale for this, and for using mg / L or moles as a unit, and I will do this going forward, but it doesn't help with the posts from the past or information from other web sites, water companies etc.
For example I would have assumed water with KH0 / GH10 would be soft, but water with KH10, GH0 would be hard?
Other way around for @_Maq_ , that way around for me.

If I was using DI and creating "designer water", I would decouple dGH and dKH (like @Roland has), but as I use rainwater, with hard, alkaline tap water (when required) as my re-mineralising agent I'm always adding 1 : 1 dGH : dKH.

cheers Darrel
 
the term "alkalinity" is preferred, because that is what we actually measure.
... and it helps avoid confusion when talking about 'hardness' and 'hard'.
But then, we must be careful when talking about 'alkaline', 'alkalinity', 'basic', 'basicity'... :(
----
There are relevant examples of natural waters where hardness is not coupled with alkalinity: East-African lakes. We are used to waters with cation content like Ca > Mg > Na > K. In East Africa it's Na > Mg > Ca > K. So, many East-African waters are soft (low Mg & Ca) but with very high alkalinity (HCO3-, CO3 2-) which drives pH up to over 9.
 
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