tap water versus filtered water - Page 2 - Orchid Board

camille1585 · #11 06-20-2009, 06:26 AM

Quote:

Originally Posted by Zdenglan

Hi all, I have tried to water my plants with water from one of these filtering doodaahs and it was not good. When i used it for misting it left white residue on the leaves. That can't be good for sure. It's mineral salts of some kind that are added during the filtration process. Currently I use water that i boiled over in a kettle. That gets instantly rid of all chlorine and some of the minerals as well. Allways using tepid water that has ambient temperature. My plants seem to be loving that. However thinking about investing into a reverse osmosis kit - that I think is the way to go for totally pure water. Costly though...

The white residues are probably not due to the filter. Filters won't remove much of the calcium in your water. So if your tap water is hard to begin with, filtering it will not made it softer, thus the residues. The residues are just not nice to look at, but they don' harm your plants.
Boiling will not remove minerals either, as minerals are not volatile. If anything, you are concentrating the minerals, as during boiling it's basically pure water which is evaporating. You could also get rid of the chlorine by letting the water sit a few hours, or over night.

RosieC · #12 06-20-2009, 06:32 AM

Quote:

Originally Posted by camille1585

The white residues are probably not due to the filter. Filters won't remove much of the calcium in your water. So if your tap water is hard to begin with, filtering it will not made it softer, thus the residues. The residues are just not nice to look at, but they don' harm your plants.
Boiling will not remove minerals either, as minerals are not volatile. If anything, you are concentrating the minerals, as during boiling it's basically pure water which is evaporating. You could also get rid of the chlorine by letting the water sit a few hours, or over night.

I've very confused by this and can only think that the filters common in the UK must be different to those common else where. Our water filter jugs claim to remove limescale (calcium carbonate) and to soften the water.

We use water from one to fill my hubbies coffee machine because it suggests doing so will reduce limescale and so far there has been no sign of it building up in the machine. We are in a hard water area though and the kettle (which just gets tap water) builds up limescale all the time.

It seems really strange to me that the UK has something different as most things are very global these days, but that's all I can think

camille1585 · #13 06-20-2009, 06:45 AM

It depends on the filters too I guess, but if your water is quite hard to begin with, the filters do remove calcium, but I don't think it removes it all. Of course, I may be talking utter BS here since i haven't used a filter since moving from the states 10 years ago. But if that water still leaves residues on the leaves, it's obvious that it was not all removed. Filters may filter things, but they don't make distilled water.

RosieC · #14 06-20-2009, 07:32 AM

Agreed, if there are white residues it sounds like calcium and if the water was first filtered it obviously did not remove it (or all of it).

Also agreed, the results of any filter will never be like distilled water.

Oh well, don't think I can answer if filtered water is good or not... it seems it depends

Ray · #15 06-20-2009, 09:21 AM

Quote:

... Currently I use water that i boiled over in a kettle. That gets instantly rid of all chlorine and some of the minerals as well.

Boiling does not remove any minerals. In fact, because you are losing water to accelerated evaporation, you're actually concentrating them in the water that remains.

Think about distillation: you boil water and then condense the vapor, giving you pure, mineral-free water, because none of the minerals evaporated in the first place.

brush · #16 06-20-2009, 09:47 AM

For my orchids I fill my water jugs with plain tap water and leave the cap off so the chlorine will evaporate overnight and it will be ready to use when I need it . I think if you have clay pots for your orchids some of the minerals from the water and even from the fertilizer that you are using for your plants will build up on the clay pots over a period of time . I just moniter that build up and scrub the pots when necessary to do so .

I think also it is important to let your water rest to evaporate the chlorine , which the orchids don't like . Having your water you use for your orchids at room temperature is a bonus for your plants too because it does not shock them when you water them.

Zdenglan · #17 06-20-2009, 05:35 PM

If i am to nitpick then if a kettle is boiling for 10 seconds then the evap rate is negligeable and concentration of minerals is not getting any higher. If you have anything but soft water then you must have noticed the coating of the kettle heating element after some time you have been using it. In my reckoning that means that the heating element actually attracts mineral salt ions from the water (as they don't stick to the plastic parts of the kettle or your watering can for that matter). Anybody any thoughts on that?

BTW My partner has done advanced physics and have just said this: When the element generates heat, water's turned into steam and generates a bubble at which point the calcium ions have a chance to attach at the heating element in form of salts. Now it depends on the overall temperature of the heated water - untill the very point the entire contents of the kettle are boiling the bubbles that form at the vicinity of the heating element deposit their calcium and rise upwards where the temperature is lower that 100 C. That results in colaps of the steam bubble that turns back into liquid (that's why kettles make the humming noise) . So it seems that it is either 'boiled water is ever so slightly less calcareous than the tap water' or 'the processes cancel each other out but it gets rid of the chlorine quicker than leaving the water stand overnight'. Anyway I'm probably going too much in depth here. Time for bed

Ray · #18 06-20-2009, 06:15 PM

Actually, to be scientific about it, the evaporation rate from boiling water is significantly greater than for room temperature water, so by default there will be some concentration of the dissolved minerals. Whether that increase is of any harm is another issue altogether, and I suspect the answer is likely "no", unless your starting water is really hard!

Zdenglan · #19 06-21-2009, 02:26 AM

I suppose you're right. Another thing I read somewhere was to soak a muslin bag full of sphagnum peat in your watering can overnight. It's supposed to slightly acidify the water by cation exchange. Any thoughts on that Ray?

breeindy · #20 06-21-2009, 03:37 AM

Hi i don't know much about water quality but i bought a rain water tank when i starting getting a few orchids just so i wouldn't have to worry. Ive also heard that rain water lacks something that orchids need and can be added by using certain fertilisers for rainwater. anyone know anything about this? Salt build up is the biggest killer isn't it? and tap water, bottled water and fertilisers have it. I flush my plants every few waterings from the top to flush any salt build ups. You can sometimes see these build ups of white around the top of the soil in bad cases.