MSU Rain mix with tap water - Calsium issue - Orchid Board

Jago · #1 08-17-2018, 06:22 AM

Hey,

I ordered the Akerne Rain mix.
Upon receiving it, I realized the CA content is quite high. Reading more into it, I found out this is actually for use with rain water (Name should have given me some indication, perhaps)

I live in the Netherlands and the water here is very rich in Calcium.
I might be able to start collecting rain water too, but ATM I only use tap water filtered through a Brita can.

Do you think the Brita can remove enough calcium?
Would the excess calcium be a problem?
Could the precipitation effect remove enough CA from the mix?

My medium is just bark and coal, with leka drainage. The bark is starting to break down, so maybe that would lead to more acidity to compensate for the CA(?).
(My orchids are mostly Oncidiums, with some Paphs and Phales)

Ray · #2 08-17-2018, 09:45 AM

A Brita filter is just activated carbon. It can remove organic chemicals and chlorine, but does not remove dissolved minerals at all, so will not affect the calcium content.

Yes, excess calcium can be a problem; it can block the uptake of other nutrient minerals.

Precipitation indicates you have exceeded the water solubility, which is significantly higher than the needs of the plants.

I guess the first questions that come to mind are "what is the concentration of calcium in your tap water" and "at what concentration will you use the rain mix?", as it is possible there will be no problem at all.

AnonYMouse · #3 08-17-2018, 03:11 PM

Can you return the rain formula? Do you know someone who uses it and have them order the tap formula?

Can you buy distilled/reverse osmosis water? At least until you can collect rain?

estación seca · #4 08-17-2018, 07:52 PM

Find the online water quality report from your water provider. Most orchids are fine if the total dissolved solids are under 200-300 parts per million. Some require less, and some tolerate much more.

Puja · #5 08-17-2018, 10:02 PM

Actually, as someone who lives in the Netherlands and has been watering their orchids (phals, oncidiums) with tap water for over 7 years, unless you are dealing with very sensitive orchids or need to water very frequently like during this dry summer it will probably be fine. I do water my miltionopsis with deep ground water, because I've been warned they are fussy.
Not sure if you can read Dutch, but here is a reference reporting on the particles found in Dutch tap water in different regions (the hardness of tap water does depend a lot on your specific region): Samenstelling drinkwater - Lenntech

Jago · #6 08-26-2018, 04:04 PM

Thanks for the help.
I decided to try to catch as much rain water as I can.
I will occasionally need to also use tap water though

Fishkeeper · #7 08-26-2018, 05:24 PM

Using water that's a bit too high in TDS now and then won't hurt the orchids as long as you can rinse them thoroughly with rainwater.

camille1585 · #8 08-27-2018, 10:14 AM

Interesting that for such a small country, water quality can vary a lot depending on the regions. Where I'm located the water is quite soft and low in calcium (29mg/L, according to the water quality report), and can easily use RainMix.

Puja, do you have an idea what the TDS would correspond to on a Dutch water report? They don't use TDS as such, but I have no idea what I should be looking for. Dutch is my third language, and I'm far from being completely fluent.
EDIT: Think I found it: "Geleidingsvermogen bij 20 °C (EGV)". And is expressed in mS/m. Thanks to an online calculator, I found that an EC of 16.8 mS/m works out to roughly 107ppm TDS.

Puja · #9 08-28-2018, 08:38 PM

Quote:

Originally Posted by camille1585

Puja, do you have an idea what the TDS would correspond to on a Dutch water report? They don't use TDS as such, but I have no idea what I should be looking for. Dutch is my third language, and I'm far from being completely fluent.
EDIT: Think I found it: "Geleidingsvermogen bij 20 °C (EGV)". And is expressed in mS/m. Thanks to an online calculator, I found that an EC of 16.8 mS/m works out to roughly 107ppm TDS.

I guess I learned something today! I had no idea you could convert those into each other. Thought that conductivity also depended on which ions were dissolved.
Incidentally, the words you were looking for are "Hardheid" and "Totale hardheid" which references the ion concentration in water. The units might be a bit confusing since PPM is an american scale (wikipedia even has it bracketed as "American degrees") European measurements often involve a number on different scales. In NL we use German degrees. 1 German degree = 17-18 PPM. In water reports this is written as Hardheid in ºD.

If you want more specific information for your exact region you can try this website (Hardheid water | Waterbedrijf Vitens) and fill in your zip code. If yours is included, you can find the exact ºD (and PPM) and PH of your specific tap water source.

Roberta · #10 08-28-2018, 10:18 PM

Quote:

Originally Posted by Puja

Not sure if you can read Dutch, but here is a reference reporting on the particles found in Dutch tap water in different regions (the hardness of tap water does depend a lot on your specific region): Samenstelling drinkwater - Lenntech

Google Translate is a very handy tool for websites in a language that you don't speak. The translation may not perfect, of course, but my experience is that the result is quite understandable. Actually, I just tried it and the Dutch to English translation was nearly perfect.