How much sodium can aquatic plants tolerate?

[xZaiox]

Wasn't sure where to post this thread, but I figured it comes under 'plant care'.

I noticed in my water report that the water supplied to my area has tested up to 112 ppm of Sodium. I'm cutting my tank water by 2/3rds with deionised water, so this number won't be as large in my tank, but still... it's got me thinking about what sort of level is acceptable for aquarium plants? I've also noticed that many of my house plants (watered with tap water) have burnt tips on their older growth.

I don't know how reliable this link is but apparently - "Most plants will typically suffer injury if sodium exceeds 70 milligrams per liter in water"

Thoughts?

 

[MichaelJ]

I can't say what the limit is, but 112 ppm seems grossly above what is acceptable. Natural fresh waterways in the tropics are typically between 1-10 ppm of Na. In fact, Na is an essential trace element, but the plants probably don't need more than tiny fractional parts per million. @John q runs his tanks at the 10 ppm level without any apparent harm to plants or livestock - may even be his secret weapon.... Others have reported tanks running well in the 30-40 ppm range (based on water reports). Again, 112 ppm can't be good for livestock or plants.

Cheers,
Michael

 

[xZaiox]

Again, 112 ppm can't be good for livestock or plants.

Yeah, the comments on @Hufsa 's journal got me thinking about sodium, and made me realise that I hadn't even looked at the content in my own tap water (https://cdn.southeastwater.co.uk/Files/Trosley.pdf) - from the file you can see the usual ppm is 32.76, but the maximum tested did come out as 112.

Based on my dilution with deionised water, I would only be receiving 1/3rd of whatever Sodium is in my tap water, but I'm definitely wanting some more understanding of how sodium effects the plants we typically keep in aquariums. It's making me wonder if it could contribute to plant damage and subsequent algae attacks.

 

[MichaelJ]

the usual ppm is 32.76, but the maximum tested did come out as 112.

Well, that changes the picture if your in 1/3rd of that range with dilution or 10 ppm or 40 ppm worst case…. not ideal, but harm may be quite limited and probably depends on plant species (?)...

I'm definitely wanting some more understanding of how sodium affects the plants we typically keep in aquariums.

Me too as this seems to be more common than we might think among hobbyists in certain regions that are fully or partially using straight tap water.

Cheers,
Michael

 

[dw1305]

Hi all,

Based on my dilution with deionised water, I would only be receiving 1/3rd of whatever Sodium is in my tap water, but I'm definitely wanting some more understanding of how sodium effects the plants we typically keep in aquariums. It's making me wonder if it could contribute to plant damage and subsequent algae attacks.

It can interfere with the uptake of potassium (K+) ions. I'm guessing that a lot of "softwater" plants aren't going to like it. Anything that grows in <"Lake Tanganyika etc. should be fine">.

from the file you can see the usual ppm is 32.76, but the maximum tested did come out as 112.

That is a lot, the "background" 30 ppm is from the <"chalk (CaCO3)">, but I wonder if the excess is <"salt water creep"> into the aquifer during the 2022 drought.

cheers Darrel

 

[_Maq_]

In fact, Na is an essential trace element

Marschner does not include sodium among essentials. I normally dose no sodium (100 % RODI water) and registered no harm.

Anything that grows in <"Lake Tanganyika

I may be mistaken but from what I know, only Myriophyllum grows there.

Yes, it can interfere with the uptake of potassium, and can negatively influence uptake of magnesium and calcium, too. Testing it is on my to-do list.

 

[dw1305]

Hi all,

I may be mistaken but from what I know, only Myriophyllum grows there.

There are actually quite a number of different plant species, they are listed in the linked thread.

They would do, I'd try Hornwort (Ceratophyllum demersum), it is <"found in Lake Tanganyika"> and really likes hard water. There are some other options in <"invasive plants of Lake Tanganyika">.

cheers Darrel

 

[_Maq_]

I've misspelled Myriophyllum for Ceratophyllum. My apology.

 

[dw1305]

Hi all,

Myriophyllum for Ceratophyllum. My apology.

I think Myriophyllum spp. also occur <"https://core.ac.uk/download/pdf/145047108.pdf">.Myriophyllum spicatum (& M. aquaticum) definitely wouldn't be worried by high sodium (Na) levels. Because they've been used for phytoremediation, we know more <"about their tolerances">.

cheers Darrel

 

[xZaiox]

Thanks for your comments Darrel (@dw1305) and @_Maq_ - interesting stuff!

That is a lot, the "background" 30 ppm is from the <"chalk (CaCO3)">

Is 30ppm normal for chalk aquifers?

I also wonder, would excess sodium manifest primarily as induced deficiencies of other elements? Or can it directly lead to damage itself? I'd love to know how an excess of sodium would typically manifest.

Hornwort (Ceratophyllum demersum)

I quite like the look of this plant, I shall remember it for the future, if I decide to give up on my current (problematic) ones

 

[John q]

@John q runs his tanks at the 10 ppm level without any apparent harm to plants or livestock

I do indeed. Minimal concentration in my tap water is 4.4 mg/l, maximum is 18.2, average is 9.8.

from the file you can see the usual ppm is 32.76, but the maximum tested did come out as 112.

It's hard to pin down harmful levels, even when looking at studies. Some plants can handle insane amounts of Na (1000ppm) without showing harmful issues, vallisneria is one of these, on the other side of the spectrum tonina probably doesn't appreciate levels above single digits.

As for your average reported Na of 32 ppm... I honestly wouldn't worry about it, lots of people manage to grow aquarium plants in higher levels than this, Aquarium Gardens springs to mind, 48 ppm Na the last time I checked their water report, and I think they manage to grow healthy ish plants in tap water.

Marschner does not include sodium among essentials. I normally dose no sodium (100 % RODI water) and registered no harm.

I don't think sodium can be classed as an essential nutrient in aquatic plants, they certainly uptake it, but may well not need it.

Does including it do any harm? I think maq needs to do a test.

 

[Jorge O'Reilly]

I'm suspecting high levels as well, which would explain some problems. Is there any way to bind sodium and make it "inert"?

 

[MichaelJ]

Some natural waterways readings for your information.

Cheers
Micharl

 

[dw1305]

Hi all,

Is 30ppm normal for chalk aquifers?

I think it is 30 ppm or more for most limestone (CaCO3) aquifers, I assume it is just because they were <"maritime deposits">. If the limestone have <"undergone dolomitization">, I think those values are likely to be higher. In the same way water that has been deep into the Earth's crust and has come to the surface as mineral, or hot springs, will have more again.

There is also ion exchange taking place in the aquifers, so I'm guessing it is <"quite a complex set of parameters">.

cheers Darrel

 

[dw1305]

Hi all,

Is there any way to bind sodium and make it "inert"?

It is difficult with monovalent ions, like sodium (Na+) because <"all the salts are soluble">. Dilution is your best bet.

cheers Darrel

 

[hypnogogia]

monovalent ions

Initially read that as “malevolent lions”. 😂

 

[dw1305]

Hi all,

Initially read that as “malevolent lions”

Well at least we'll be <"able to re-find this thread">, that must be the UKAPS equivalent of a <"Googlewhack">.

Probably should have said that monovalent ions are "ions that carry a single charge", like sodium (Na+), a monovalent cation, or nitrate (NO3-), a monovalent anion.

cheers Darrel

 

[_Maq_]

Initially read that as “malevolent lions”. 😂

Malevolent lions can be diluted, too.

 

[MichaelJ]

It's hard to pin down harmful levels, even when looking at studies. Some plants can handle insane amounts of Na (1000ppm) without showing harmful issues, vallisneria is one of these, on the other side of the spectrum tonina probably doesn't appreciate levels above single digits.

Absolutely right @John q - as a matter of fact, with appropriate acclimation, a lot of popular easy plants can thrive even in brackish water (way above 1000 ppm Na)... including some Vallisneria species, some Anubias species, Java Fern... among others. Of course, for livestock its a different story all together.

Cheers,
Michael

 

[Hufsa]

a lot of popular easy plants can thrive even in brackish water (way above 1000 ppm Na)... including some Vallisneria species, some Anubias species, Java Fern... among others. Of course, for livestock its a different story all together.

Could we use another parameter, a value, GH, KH, another mineral, or something, to estimate how much Na a plant species might tolerate?
Because I suspect it differs quite a lot from species to species.
As you say, some plant species can grow in brackish. So for those a higher (whatever that is) Na level would not be a concern.
But could we sort of guesstimate in the other direction?
For example, if a plant comes from extremely solute poor waters, is it then more likely to be intolerant of Na?

Semi off topic, I heard somewhere that because of salting roads (for cars), the plant species growing next to the roads are being altered in favor of more salt resistant species.
I havent checked if its true though.
Perhaps in a slightly similar way, the closer a plant grows to the coast, or on geology that contains Na, the more salt it will be able to handle?
Its all about evolution after all isnt it.. The plants who couldnt handle higher Na and were exposed to higher Na from their environment died, leading to species with tolerance.
No exposure = no tolerance (?)