Water quality for paphs

[Marc]

As far as I know rainwater is preferred over tapwater to water orchids but I don't have an unlimited supply of rainwater so I've allready used tapwater for watering my plants and probably will do so in the future as well.

I've recieved a sheet from the company that I get the tapwater from but it's so much data that I don't know what to look for.

I also looked up information ladyslipper.com and I can't reach the "water quality issues for slipper orchid growers" section.

And the "mineral Nutrition for slipper orchids growers" section states a few values in ppm. ( http://ladyslipper.com/minnut.htm )

I'll put down the values for the elements mentioned on the link above as provided by the water company. The values are give in mg/l though.

PH = 7.5 - 8
NO3 = 2.5 mg/l
NH4 = 0.025 mg/l
Calcium = 78.25 mg/l
Magnesium = 7.4 mg/l
Phosphorus = not mentioned / PO4 = 0.015 mg/l
Sulfur = not mentioned / SO4 = 76mg/l
Boron = 0.025 mg/l
Iron = 0.0081 mg/l
Manganese = 0.0050 mg/l
Zinc = 0.005 mg/l
Copper = 0.0025 mg/l
Molybdenum = not mentioned

I hope that someone can help me out, chemistry classes were a long time ago.

I would like to know how "bad" my tap water is for my plants. And what to look out for when starting with fertilizer.

edit:

Did some google-fu and according to most sites I can state that 1mg/l = 1ppm for water based solutions. So essentialy that would result in calcium and perhaps sulfur to be to high? Any other elements or stuff i need to look out for?

 

[NYEric]

Chlorine!

 

[suss16]

Or even worse, Chloramine... check for it. We have great tap water, but it contains Chloramines - I now use a special carbon filter to remove.

 

[Shiva]

One way to avoid tap water is with a Reverse Osmosis system. I use rainwater in spring, summer and fall and RO water the rest of the year.

 

[werner.freitag]

1mg/l is the same as 1ppm

 

[Clark]

Sweet.

 

[Rick]

This water is hard and somewhat alkaline.

your hardness is 224 (not very good in long run)

You have a small amount of nitrogen and phosphate, and sulfur is not too high. (good)

the metals are trace (good)

I didn't see any mention of TDS, conductivity, sodium or chloride, but they are usually abundant in hard water.

The chlorine or chloramines come out easy with carbon (like a Britta filter if you just want to make small portions).

Only a reverse osmosis, distillation, or ion exchange system will reduce the salts.

My well water is not too dissimilar to your tap water. (except no chlorine)

What I do is blend about 10% of my hard salty well water with RO (pure water) I take home from work. (I work in a tox lab and have access to gobs of pure water). You could buy distilled water or collect rain water also.

Over the ten years I've been growing, I have gone from use of my well water to only RO, to the 10% blend, which is by far my most superior results.

 

[Rick]

Also the Calcium to Magnesium ratio is about 10:1

So I wouldn't do any calcium supplementation in your potting mix, but I would be spiking more with Epsom salts to balance the Magnesium

 

[suss16]

Rick, my experience with chloramine removal from my domestic water was a bit different. I tried a few different chlorine/chloramine removal systems, none of them removed chloramine until I installed a Pentek ChlorPlus 10 Carbon Block, specifically designed to remove chloramines. Yes it is a carbon based filter, as you mentioned in your post. But I tried other carbon based systems for chlorine removal that did not work.

Did it make a difference with my plants? Well, er... I think so? Yes, my plants are growing much better in the last two years - but then again, I made a bunch of cultural changes based on the information from Slippertalk and other sites.

 

[Rick]

Rick, my experience with chloramine removal from my domestic water was a bit different. I tried a few different chlorine/chloramine removal systems, none of them removed chloramine until I installed a Pentek ChlorPlus 10 Carbon Block, specifically designed to remove chloramines. Yes it is a carbon based filter, as you mentioned in your post. But I tried other carbon based systems for chlorine removal that did not work.

Did it make a difference with my plants? Well, er... I think so? Yes, my plants are growing much better in the last two years - but then again, I made a bunch of cultural changes based on the information from Slippertalk and other sites.

I use all sorts of carbon (except the cheap "anthrocite" )junk sold in department store pet supplies. They will all work, but you may need to tweak the contact time (flow rate past the carbon)to get good results. It depends how much TRC and how fast the water is flowing past the carbon. Your system is probably nicely engineered to control contact time past the carbon, rather than made from a carbon that is more effective than others for reduction of chlorine.

Alternatively you could also batch remove TRC by adding sodium thiosulfate ("DeChlor" from your aquarium supply). Since you should have no more than 3 or so ppm (mg/L) of TRC you only need that much to neutralize the chlorine, so you only generate a few ppm of salts in the process(a tiny fraction of what is already there).


In Marc's case, TRC is not his only problem, his water is too hard and salty. And carbon won't touch salts.

 

[Marc]

Everyone and espescially Rick thanks for the excellent input so far.

I didn't see any mention of TDS, conductivity, sodium or chloride, but they are usually abundant in hard water.

Sodium = 20.5 mg/l
Chloride = 34.7 mg/l

TDS = Total Dissolved Solids?

Can't find that in the table provided, however there is the following value: Total Hardness : 2.2625 mmol/l

Conductivity is also not mentioned on the sheet provided by my supplier.

 

[Rick]

Everyone and espescially Rick thanks for the excellent input so far.



Sodium = 20.5 mg/l
Chloride = 34.7 mg/l

TDS = Total Dissolved Solids?

Can't find that in the table provided, however there is the following value: Total Hardness : 2.2625 mmol/l

Conductivity is also not mentioned on the sheet provided by my supplier.

Actually the Na and Cl are not all that high, which is good, so despite the hardness the TDS (yes total dissolved solids) or conductivity will not be that high.

The units for the hardness concentration I derived is mg/L as CaCO3, rather than in grains or mmol/L. It should convert to the same number. There is a standard formula for calculating hardness of 2.48X Ca mg/L + 4.11XMg mg/L = hardness in mg/L as CaCO3

Thats what got me to the 200+ I came up with.

For USEPA (and EU) the hardness designations are harmonized.

~20 - 25mg/L =very soft
~40 - 50mg/L = soft
~80 - 100 mg/L = Moderately hard (standard for EPA toxicity testing)
~160 - 200mg/L = Hard water
~320 - 400mg/L = Very hard water.

I think cultivated orchids like stuff in the soft to very soft range generally for long term. I know some very succesful growers like Ed M in my local area that use the tap water which is at the low end of mod hard. I'm not familiar with too many succes storys from folks with growers in the hard to very hard range.

If you wanted to duplicate the hardness of Ed's water you would cut your water 1 part your water 2 parts with distilled or Reverse Osmosis water.

From studying the local water here, I do know that the Ca to Mg ratio is less than 4 to 1 rather than the 10:1 of your water. So I would cut even more so and add some Mg from Epsom salts ("Bitter Salts" in EU)

 

[Rick]

A milli mole of CaCO3 = 100mg.

so 2.26 mmol/L hardness is equivalent to 226 mg/L (as CaO3).

Pretty dang close to the 224 I came up with:wink:


Does your report have alkalinity or bicarbonate values?

 

[Marc]

A milli mole of CaCO3 = 100mg.

so 2.26 mmol/L hardness is equivalent to 226 mg/L (as CaO3).

Pretty dang close to the 224 I came up with:wink:


Does your report have alkalinity or bicarbonate values?

Bicarbonate = HCO3 = 182.25 mg/l

I've found conductivity as well, take note it's in microsiemens / meter

Conductivity = 48 mS/m ( = 0.48 mS/cm acc. to http://fw.farmonline.com.au/budget/archive/2008/Metric_Conversions.pdf right side of screen, above tank capacities )

 

[Rick]

Bicarbonate = HCO3 = 182.25 mg/l

I've found conductivity as well, take note it's in microsiemens / meter

Conductivity = 48 mS/m ( = 0.48 mS/cm acc. to http://fw.farmonline.com.au/budget/archive/2008/Metric_Conversions.pdf right side of screen, above tank capacities )

You guys do crazy unitsoke:oke:

we use uS/cm (so X1000) so that would be 480 in my lab.

For reference the Nashville tap water I've been comparing your water too has a conductivity of ~ 200 uS/cm

The alkalinity fits the pattern.

I think dilution is your best strategy if you have a small indoor collection.

 

[Marc]

You guys do crazy unitsoke:oke:

we use uS/cm (so X1000) so that would be 480 in my lab.

For reference the Nashville tap water I've been comparing your water too has a conductivity of ~ 200 uS/cm

The alkalinity fits the pattern.

I think dilution is your best strategy if you have a small indoor collection.

I talked about this with my brother yesterday and he's working in agriculture. He stated that the standard for them is mS/cm.

So to summarise it all my tapwater isn't that bad it's just the hardness that could be bad for my plants in the long run?

 

[Rick]

I talked about this with my brother yesterday and he's working in agriculture. He stated that the standard for them is mS/cm.

So to summarise it all my tapwater isn't that bad it's just the hardness that could be bad for my plants in the long run?

I haven't seen anyone post that their plants are doing great using hard water, but know of lots of people doing great with softer water, so the answer would be yes (depending on your definition of "long run".

Did you ever find out how much/if chlorine is in it? (maybe under TRC).

 

[Marc]

I haven't seen anyone post that their plants are doing great using hard water, but know of lots of people doing great with softer water, so the answer would be yes (depending on your definition of "long run".

Did you ever find out how much/if chlorine is in it? (maybe under TRC).

On the website of my supplier it's clearly stated that they don't add any chlorine to the water. I'm lucky regarding that because they pull their water from the ground. When you live towards the north western part of the Netherlands a lot of surface water is use for tapwater and it has a nice dose of chlorine added to it.

 

[NYEric]

Um, if they don't add chlorine whats killing the bacteria in the water and pipes?

 

[Marc]

Um, if they don't add chlorine whats killing the bacteria in the water and pipes?

According to the dutch wiki for tapwater UV-light + ozon.

Chlorine is banned in tapwater since 2005.