Water types?

[Ro3bert]

OK, so I know what distilled and spring waters are but what is RO water?

I plan to use only distilled water in my (planed) terrarium but may change to RO if it seems to be be better. Rain water is out for me.

Robert

[trdyl]

RO(reverse osmosis) is the next best thing to distilled. But the older filtration systems uses about 4 gallons or more gallons of water for every gallon of filtered. There does seem to be a zero waste system available.

[Ro3bert]

Originally Posted by trdyl

RO(reverse osmosis) is the next best thing to distilled. But the older filtration systems uses about 4 gallons or more gallons of water for every gallon of filtered. There does seem to be a zero waste system available.

Ted,

I know what an RO system is for a house but am unaware of that usage ratio. Would you (or someone else) explain (in simple English)?

I probably will not be using more than 2 gallons (purely a guess) for the water feature.

Robert

[MrHappyRotter]

RO (reverse osmosis) water is pretty darned pure. I have one of those cheap TDS meters, and RO is pretty much indistinguishable from rain and distilled water from that standpoint.

I use rain and RO almost exclusively for watering. In my conditions, I water most plants twice a week. On the weekend is the drenching watering, and that's also when I typically fertilize. During the week, normally on Wednesday, is when I do a quick spritz.

But back to the topic. RO works well. I typically mix in tap water at a 1:4 or 1:5 ratio (one part tap to 4 or 5 parts RO). This usually leaves me with a TDS reading of around 20 - 40 ppm, which is good.

The reason for mixing back in tap water is ....

For one, very pure water is too pure for most plants in the long run. It can actually leach out too many nutrients.

Second, there are good minerals and nutrients in tap water, such as calcium and magnesium. Adding in a bit of tap water, adds a bit of those things.

Third, the minerals in tap water, along with other compounds, act to buffer the water pH. That helps prevent the pH in the potting mix from going too acidic or too basic. The most important thing for plants is to keep things stable. A bit of tap water goes a long way in this regard.

Hope that helps.

[Ro3bert]

How do you collect and store rain water? It sounds good and in our area we get enough rain to consider using it.

Robert

[Orchid Whisperer]

Originally Posted by Ro3bert

How do you collect and store rain water? It sounds good and in our area we get enough rain to consider using it.

Robert

Hi Robert

Walmart and similar stores sell plastic storage boxes that are meant to go under a bed. These are rectangular, about 32" L x 20" W x 6" H. I place some of these out on my deck when a significant rain is expected. Cheaper than getting a rain barrel for your down spout, but that can work too. Really, you can use just about any clean plastic container to catch rain water.

I filter any rain water that I plan to store for a long time (to remove leaves, bugs, etc.). You can run the water through one of those plastic "permanent" coffee filters, set into a funnel on top of your storage container. You can also use a paper towel & funnel to do the filtering.

Store the rain water in any clean plastic container. I use gallon milk jugs, washed with detergent & rinsed well.

BTW, I use rain water sometimes, and tap water at other times. This gives some variation in pH, which is beneficial since some plant nutrients are best utilized at low pH (rain water), while others are best utilized at neutral pH (tap water).

[Ray]

The "waste" water in an RO system is used to sweep away the dissolved solids rejected by the membrane.

The "optimal" design of the original ones was 3:1 = for each gallon of pure water produced, 3 gallons were used to flush the membrane housing. Residential systems that fill bladder tanks start there, but as the tank fills and the pressure in it builds, it slows the pure water generation, so that ratio increases.

I don't know if there have been changes in membrane technology, but decreasing that ratio, which theoretically should require earlier membrane replacement, doesn't seem to hold true. Most of the systems I sell are on the order of 2:1; some as low as 1.5:1, and there are no issues.

There were two articles published in the AOS Orchids magazine on this subject, by one of my favorite authors:

Water Your Orchids

Reverse Osmosis

And that business of pure water "leaching" nutrients from plants is a myth. There have been scientific studies that prove otherwise, and if you think about it, in nature, the only water the plants see is nature's version of distilled water - rain and dew - and while it may contain nutrients washed down out of the forest canopy, that concentration is very low (studies have show 15-25 ppm TDS), and only has those nutrients for the first few seconds after it starts raining. After that, it's pretty much zero.

[Paul]

Rotter, but something one must consider is the quality of one's tap water. All are not created equal. Municipal water is often treated with chlorine and/or fluorides -- neither of which is a desirable addition to one's media.