TDS water level for P. rotschildianum, P. philipinense, and P. St. Swithin

[King_of_orchid_growing:)]

Originally Posted by Roberta

I'd say that if lead or copper were high enough to significantly add to the TDS, the water would be classed as toxic waste... At least in the US (and I think the EU is even more strict) the limit of lead in drinking water is in the low parts-per-billion range, copper around 1 ppm.

You're right, but they're still part of the TDS value.

As is sodium, as you had pointed out a couple times.

TDS values are not specific enough to deal with specific minerals being tracked. In the case of Paphs, those would be calcium and magnesium.

To say there's success with a particular orchid using a TDS value, doesn't necessarily point to which mineral is the result of that success when there are a bunch of factors to parse out.

What if it was something plants actually use in significant quantities like potassium or phosphorous? They come in both organic and inorganic forms and can be water soluble in some cases. Can you tell now?

[estación seca]

Most of the water quality reports I've seen people discuss here do mention something about calcium and magnesium content. Sometimes it is disguised as total hardness or grains of hardness or the like. It is easy to look up what these mean. There are not many ions contributing to total dissolved solids in drinking water other than magnesium and calcium salts. Sodium and iron are not desirable minerals in drinking water so they are often shown individually on water quality reports, and are usually present in small amounts. So it is safe to think most of the TDS comes from calcium and magnesium salts.

The amount of both of these isn't very important so long as some is provided.

There's no such thing as a TDS meter. There are meters people can buy that call themselves TDS meters. They measure the total number of charged particles in the water. You can't tell what the actual total dissolved solids are without knowing the exact amount of each ion in solution. This has been discussed on Orchid Board at great length before, so I suggest people look up the old discussions rather than rehashing it here.

[King_of_orchid_growing:)]

Originally Posted by estación seca

Most of the water quality reports I've seen people discuss here do mention something about calcium and magnesium content. Sometimes it is disguised as total hardness or grains of hardness or the like. It is easy to look up what these mean. There are not many ions contributing to total dissolved solids in drinking water other than magnesium and calcium salts. Sodium and iron are not desirable minerals in drinking water so they are often shown individually on water quality reports, and are usually present in small amounts. So it is safe to think most of the TDS comes from calcium and magnesium salts.

The claim you make of desirability of sodium and iron in drinking water is not in the least bit correct. As humans we need both these minerals, granted not in large quantities to cause toxicity to our systems.

There's the assumption that much of the TDS value is the result of calcium and magnesium, but what if there were also measurable amounts potassium and phosphorous (which are desirable minerals for drinking water too) present as well?

It would make for a bad claim to say that someone had success due to a certain level of TDS. Hypothetically, if the potassium or phosphorous had been the factors for success and not necessarily the calcium nor the magnesium, how's this claim logically sound?

Originally Posted by estación seca

The amount of both of these isn't very important so long as some is provided.

That's an overgeneralization. If this were the case, why would we be so careful to control for these minerals with plants that are sensitive to these minerals such as with Lepanthes?

Originally Posted by estación seca

There's no such thing as a TDS meter. There are meters people can buy that call themselves TDS meters.

Well, what else would we be talking about? This is the device most people have called a "TDS meter" to measure TDS.

Originally Posted by estación seca

They measure the total number of charged particles in the water. You can't tell what the actual total dissolved solids are without knowing the exact amount of each ion in solution. This has been discussed on Orchid Board at great length before, so I suggest people look up the old discussions rather than rehashing it here.

Yeah, no kidding. I think I brought it up years ago. Thank you for reminding me.

By the way, thank you for making my point for me.

[thefish1337]

I think the discussion in this post is beyond what the OP asked for. Seems like his TDS is just fine- pedantic discussions aside.

[King_of_orchid_growing:)]

Originally Posted by thefish1337

I think the discussion in this post is beyond what the OP asked for.

Maybe...

Originally Posted by thefish1337

Seems like his TDS is just fine

It is "just fine", and also not of much value. I've said so too.

Originally Posted by thefish1337

- pedantic discussions aside.

Not quite so pedantic if the goal is to narrow down the factors that matter (in the case of Paphs, they're calcium and magnesium + NPK with everything else being relatively lower in importance).

If you find my discussions rather annoying, as you stated, no one's forcing you to read any of it.

[Ray]

I had a fairly high mineral-laden well in PA, so always used RO. When I moved to NC, I sent a water sample off for analysis, and received the attached info.

We are near salt water (ocean - 1 mile, Intracoastal Water Way - 75 ft.), but our water comes from municipal wells about three miles from the ocean tapping a relatively shallow aquifer, supplemented by Cape Fear River water. Lime is added to "sweeten" the taste.

I add that analysis, as it shows a "normal range" for the various results, but keep in mind that is for terrestrial plants, not epiphytes, and where that range is given as "0.00-0.00", it means it varies all over the map, not that zero is right.

[Dusty Ol' Man]

Originally Posted by Ray

if only...

Unfortunately, that's not universally true. The water quality reports required for publication in the US relate to safety, so bacterial loading, heavy metals, and some toxic chemicals may be listed, but way too many of them don't tell you a damned thing about the minerals we would like to know.

This is true for my city. If I want to know anything further I have to call them.

[jantigercat]

Thank you so much for the information regarding the TDS level and for checking the water report in my area. I’ve learned a lot from the discussion! :-)

I am including the link here of the water report from my city: https://www.mvv.de/fileadmin/user_up...et-rheinau.pdf

[King_of_orchid_growing:)]

For those interested in reading Jantingercat's water quality report in the city of Mannheim, Germany, the values that are from the test sample look like they're under the column that says, "Trinkwasser Rheinau".

Trinkwasser = drinking water

Rheinau is probably referring to the Rhein River.

The water parameters of interest are:


Plant macronutrients:

Ammonium (NH₄⁺): <0.01 mg/L
Nitrit = nitrite (NO2−): <0.05 mg/L
Nitrat = nitrate (NO3-): 22 mg/L

Phosphat = phosphate (PO₄³⁻): <0.5 mg/L

Kalium = potassium (K): 2.19 mg/L

Sulfat = sulfate (SO₄²-): 81 mg/L

Calcium (Ca): 108 mg/L
Magnesium (Mg): 21.1 mg/L
Hydrogenkarbonat (berechnet) = hydrogen carbonate (calculated) = bicarbonate (calculated) [HCO3-]: 325 mg/L

https://www.extension.uidaho.edu/pub...IS/CIS1124.pdf


Concentration of Calcium & Magnesium in the water:

Gesemtharte = overall hardness = general hardness (GH): 19.9 dH
Gesemtharte (berechnet) = general hardness (calculated): 3.56 mmol/L [mmol/L = millimols/Liter]


Plant micronutrients:

Chlorid = chloride (Cl): 45 mg/L
Eisen = iron (Fe): <0.007 mg/L
Kupfer = copper (Cu): <0.002 mg/L
Mangan = manganese (Mn): <0.002 mg/L
Nickel (Ni): <0.002 mg/L
Bor = Boron (B): 0.046 mg/L

https://www.extension.uidaho.edu/pub...IS/CIS1124.pdf


Elements plants can uptake, but it's not clear as to their benefits:

Strontium (Sr): 0.27 mg/L

Uptake of Stable Strontium by Plants and Effects on Plant Growth | SpringerLink

Selen = selenium (Se): <0.001 mg/L

Frontiers | An Overview of Selenium Uptake, Metabolism, and Toxicity in Plants | Plant Science


"Non-essential" element, but still plays a role for plants:

Natrium = sodium (Na): 29.4 mg/L

Plants and sodium ions: keeping company with the enemy



Toxic elements/compounds to plants:

Antimon = antimony (Sb): <0.0005 mg/L
Arsenic (As): <0.001 mg/L
Benzol = benzene (C6H6): <0.5 micrograms/L
Blei = lead (Pb): <0.001 mg/L
Cadmium (Cd): <0.0005 mg/L
Chromium (Cr): <0.002 mg/L
Fluoride (F): <0.15 mg/L


Herbicides:

Atrazin = atrazine (herbicide): <0.05 micrograms/L

to

Triallat = triallate (herbicide): <0.05 micrograms/L



Note: The numerical values are those that were present in the water sample being tested. It does not reflect the concentrations needed by plants [orchids].

[jantigercat]

Great to read the translation, King_of_orchid_growing!

Actually there are two major sources of water in Mannheim. I chose the report on Rheinau because it's nearer where I live. The sodium level is higher in Rheinau than the other source (Käfertal) could it be because of the location? Rheinau lies closer to the river Rhine.

Here is the report of the other source: https://www.mvv.de/fileadmin/user_up...-kaefertal.pdf