RO vs Distilled water: same or different? - Orchid Board

VMStearns · #1 03-15-2014, 12:40 PM

My beloved and I both use a machine that requires distilled water so we always have it around the house and I am considering investing in a small countertop distiller.

That said, is there any difference as far as the orchids are concerned between RO and Distilled water. My thinking is that there wouldn't be because distilled water is the closest thing to rain water in industrialized areas because it is formed via evaporation. I'm assuming that the primary benefit to RO is its lower cost.

Can anyone confirm or educate me???

PaphMadMan · #2 03-15-2014, 01:16 PM

Distilled water and RO water are indistinguishable. Both are simply purified water with minimal dissolved minerals or organic material. Both are variable in quality, not necessarily quite perfectly pure, but the impurities are in the few parts per million range and meaningless for all but the most stringent laboratory uses. Both are usually cleaner than rain water by the time you have collected it.

Neither is free or effortless to produce - distilling takes energy input and RO systems can use a lot of extra water - and both require some maintenance, etc. The choice is yours based on cost, convenience, volume needed, etc. Only you can determine what those would be for your situation.

For very small volumes, a gallon or 2 a week, it is probably most efficient to buy bottled distilled or RO water, or there are filtration systems such as ZeroWater that are very effective and convenient. The higher the volume you need the more likely an RO system is the way to go. There are situations where distilling might make sense.

VMStearns · #3 03-15-2014, 01:26 PM

Thanks PaphMadMan. Your answer confirmed my thinking. I've been toying with the idea of working on building a small still that could be used during our few sunny days. I know it wouldn't generate much (few gallons maybe), but free is free, right???

I'm painfully aware of the expense, both up-front and energy, required for a home distiller. I'm still in the thinking and analyzing stage and will more than likely wind up sticking with the current .89 per gallon at the discount grocery.

Thanks again! The Orchid Board is awesome!

PaphMadMan · #4 03-15-2014, 01:30 PM

A solar still is cheap to operate but somewhat labor intensive in the long run. Do you want maintaining the still to be one of your hobbies? And what happens if you don't have sunshine for a week?

VMStearns · #5 03-15-2014, 01:33 PM

Haven't decided yet. I'm still in the research stage. I'm not willing to invest a lot until I know what I might be getting into. Right now, I'm looking for plans on the Internet to figure out the feasibility.

james mickelso · #6 03-15-2014, 06:18 PM

Distilling is the process of applying heat to boil water and then condense that vapor back to a liquid in which case the water should be pure with no contaminates. Reverse osmosis (RO) is a process of applying pressure to squeeze water through a permeable member filter which in theory removes the contaminates from the filtrate. Distilling in theory produces pure water whereas RO produces water with possible contaminates depending on how fine the filter membrane is. Distilling takes considerable energy in the form of heat whereas RO takes less energy but produces a brine which is the water used to back flush the filter membrane. Whewwww!!!! In Washington your water should be very clean to start with because your water flows through mostly igneous derived gravels and soils. Even in eastern Washington most soils are igneous derived. I'd love to have your water. I buy my water from those RO water machines out front of the local supermarkets. $.25 to $.35 a gallon. I use about 20 gallons to water my 125+ orchids.

VMStearns · #7 03-15-2014, 11:12 PM

Ahhh....I forgot to mention an important fact. I use distilled water when I mist my orchids. I don't like spots on the leaves or on my windows. Though our water is indeed quite soft (and YES...after living in Arizona and the DC area for a decade, I LOVE Washington State water...even from East of the Cascades) it does have dissolved minerals and salts that cause spots.

I have been using tepid tap water to fertilizer weakly, weekly and for the monthly flush.

DavidCampen · #8 03-15-2014, 11:16 PM

RO will be more convenient and less expensive than distilled.

james mickelso · #9 03-15-2014, 11:24 PM

Why do you mist your orchids? It does nothing for the orchid. The water evaporates before it does the orchid any good. Humidity? It doesn't increase the humidity and your orchids don't need the humidity especially on the tops of the leaves. Even misting the bottoms of the leaves does little for them. Renton is a nice area. Been there a few times but not in the recent past. Got stuck there hitch hiking back around 64 or 65. Farmers didn't like young people hitch hiking back then. Supplying the root environment with some humidity is ok but your watering regimen should keep them humidified. I like distilled water but the cost is quite high. Do you happen to know the TDS of your water? pH?

VMStearns · #10 03-16-2014, 05:57 PM

James,

I've been misting my orchids because I read somewhere that it was good for them. If it does nothing...my husband will likely be thrilled that he doesn't have to do it any more.

All my orchids, (except the new one that is in isolation and I did get a pebble tray set up before I left) sit on top of pebble trays to increase the humidity.

I don't have any instruments yet to measure humidity, TDS (I assume total dissolved solids) or Ph. I'll be purchasing them over time. If there is any one instrument that you depend on most, I'm open to recommendations.