29 replies to this topic

[MalcolmP]

I used to use a cation exchange (to remove calcium and magnesium ions>to hydrogen) resin in the days when RO membranes were frightfully expensive, but messing with conc. hydrochloric acid was a pain (sometimes litterally !).
Eventually a local horticultural lab had excess RO so things were easy for a few years till PM Thatcher decided that gov. funded research was a no-no, the lab and its fields became a housing estate.
Result was that I now have approx 1500L / 320gal of rainwater storage in 7 containers :) ! much easier to manage ;)

If I was to do it all again I would just buy a domestic RO unit, they are sooo cheap now !

Edited by MalcolmP, 24 July 2012 - 22:41 PM.

[mobile]

MalcolmP, on 24 July 2012 - 22:34 PM, said:

If I was to do it all again I would just buy a domestic RO unit, they are sooo cheap now !

I got a 3 stage RO unit off eBay for £22! Arguably I don't need it, as the water is so soft here, but I like to play safe.

[Marcia]

Someone has tipped my bucket of rainwater over!!! I'm now back to square one with only a small amount left.

I've checked out my water supplier and this is the information i have been given for drinking water in my area -

Avg hardness - 44.75
Hardness - 17.9
Classification - Soft
Degrees Clark - 3.13
Degrees German - 2.51

Is this safe to use for my plants if my rainwater supply runs dry?

[jimscott]

What are Clark & German?

[Marcia]

I have no idea.

This is the information i found on it.

Quote

The various alternative units represent an equivalent mass of calcium oxide (CaO) or calcium carbonate (CaCO3) that, when dissolved in a unit volume of pure water, would result in the same total molar concentration of Mg2+ and Ca2+. The different conversion factors arise from the fact that equivalent masses of calcium oxide and calcium carbonates differ, and that different mass and volume units are used. The units are as follows:
Parts per million (ppm) is usually defined as 1 mg/L CaCO3 (the definition used below).[16] It is equivalent to mg/L without chemical compound specified, and to American degree.
Grains per Gallon (gpg) is defined as 1 grain (64.8 mg) of calcium carbonate per U.S. gallon (3.79 litres), or 17.118 ppm.
a mmol/L is equivalent to 100.09 mg/L CaCO3 or 40.08 mg/L Ca2+.
A degree of General Hardness (dGH or German degree (°dH, deutsche Härte) is defined as 10 mg/L CaO or 17.848 ppm.
A Clark degree (°Clark) or English degrees (°e or e) is defined as one grain (64.8 mg) of CaCO3 per Imperial gallon (4.55 litres) of water, equivalent to 14.254 ppm.
A French degree (°F or f) is defined as 10 mg/L CaCO3, equivalent to 10 ppm. The lowercase f is often used to prevent confusion with degrees Fahrenheit.

[David Ahrens]

It all depends on how many plants you have. I live in a flat and don't have a huge lot of plants, some on the windowsill, and some in a Nepenthes tank.
I have used a distiller for a number of years now when I can't get rainwater. I just run off a gallon in about four hours when I need one, simple, no mess and no waste water. It looks like a mini dalek when you put tapwater in and distilled water comes out of a spout.
You can Google distiller and see what you get. Mine is an Ecowater distiller, which is an American brand.  I got mine from the Holistic Research Centre who used to be near Cambridge but I believe that they are somewhere in Hertfordshire these days, again try Google.
If you need a lot of distilled water, the downside is they can use a lot of electricity. It should be possible to run off three gallons per day which would be enough  for a six by ten foot greenhouse to get by on.  They are far cheaper, however than buying deionised water commercially. Mine works out about 15 p per gallon, half that if you are on Economy seven.
I have had my distiller for a number of years and mine was £130 new. I understand that they are quite a bit more than that now. To a degree, you get what you pay for.
This conversation does come up on the forum from time to time. Carl (Mobile) always like deionising filter systems and for some reason doesn't like distillers. The downside with deionising systems is that they need to be used otherwise it buggers the filter. They are also very wasteful of water, you get five gallons of waste water for every one gallon of deionised water.
It all depends how much water you need.

Edited by David Ahrens, 28 July 2012 - 00:59 AM.

[David Ahrens]

Just done a bit of Googling, the supplier that I mentioned is the Holistic Research Company. They are near Royston, they didn't move all that far down the road. They are doing a unit for £198 on special offer at the moment. A bit of money to lay out but they last for years.

[mobile]

David Ahrens, on 28 July 2012 - 00:52 AM, said:

This conversation does come up on the forum from time to time. Carl (Mobile) always like deionising filter systems and for some reason doesn't like distillers.

I have nothing against distilled water, except the running cost of the distiller and have stated that purchasing large quantities of deionised water works out expensive: http://www.cpukforum...ndpost&p=244581

You have to admit though, that for short term emergencies, purchasing deionised or RO water is the far cheaper than buying a distiller, RO unit or deioniser cartridges.

Nowadays I use a reverse osmosis system, which does require a filter change from time to time but the whole system was only £22 and the occasional carbon filter change is cheap enough. In addition, where I live I could get away with using tap water for my plants.

[David Ahrens]

I think if I had a greenhouse and maybe needed fairly large amounts of water, then the deioniser would be the solution. I must have had the still for 15 years or more, so the cost per year doesn't work out much.
You pays your money and takes your choice, there are a;ways things that you can do.

[Marcia]

I don't have alot of plants. I have one 30cm pot containing 3 VFT, one small 6.5cm pot containing a Drosera and i will be filling just one more 30cm pot of VFT in the next week (maybe) so i don't need an awful lot of water.

As it turns out, the heavens opened yesterday afternoon and more rain is forecast over the next 4 or 5 days so i can start building up my supply of rain water again.