How Pure Does Water Need To Be To Be Pure Water

[Lil Duck]

Hello everyone, currently my city is running off of a blend of well water and small ugly reservoir water. As such my tap water now has a TDS of 125 and a conductivity of around 275 uS/cm. For the past 2 months I have been using the ever abundant rain water California has been getting but I am about to run out. Because I'm usually spoiled with awesome cold pure delicious snow melt fancy water with a TDS of around 30 and a conductivity of 50 uS/cm, I am now being forced to use my pure water fertilizer with water that to me is (terrible tasting) liquid rocks (I even get water spots on my shower walls now! Can you believe this injustice?? ) This begs the question, at what threshold does water stop being pure, to me that threshold is 100 TDS or about 175 uS/cm but I would like to know what other peoples threshold is. I use MSU RO mix if that helps.

[Roberta]

With all that good water around you're getting WHAT? Not that wonderful Hetch Hetchy snow-melt water???

My RO water is typically around 15 ppm TDS, when the membrane is pooping out may go as high as 30 but then it's time to change it. For MSU RO formula, I'd probably make 50 ppm the cutoff but 100 probably is bearable for the short run. Most orchids would still consider that pretty good, except for the really sensitive ones. (Except for the sensitive ones for which I use RO, most of my orchids get city water that ranges from around 200 on a really good day to 400 on a bad one, average usually between 250 and 350, but I fertilize everything with the good stuff so I can do it indiscriminately)

Here's hoping that once the snow melt gets going you get your good water back!

[Lil Duck]

Originally Posted by Roberta

For MSU RO formula, I'd probably make 50 ppm the cutoff but 100 probably is bearable for the short run. Most orchids would still consider that pretty good, except for the really sensitive ones.

Thanks Roberta, I do in fact have some really sensitive ones so it looks like I'll have to buy some RODI water from the fancy expensive aquarium store until this part of the globe starts warming again.

[Dusty Ol' Man]

Originally Posted by Lil Duck

Thanks Roberta, I do in fact have some really sensitive ones so it looks like I'll have to buy some RODI water from the fancy expensive aquarium store until this part of the globe starts warming again.

Your local Walmart should have an RO dispenser. Mine sells it for $0.29/gal. Bring your own bottle(s).

[Roberta]

Before using that commercial water, I'd sure test... who knows when they last serviced the unit. Where I live, the water dispensers give out "drinking water" with some unknown amount of minerals either left in or returned, to give the water some taste. (Very pure, like zero TDS, water is pretty tasteless) And many of those units have also turned out to be petri dishes when tested. So caveat emptor.

[Lil Duck]

Originally Posted by Dusty Ol' Man

Your local Walmart should have an RO dispenser. Mine sells it for $0.29/gal. Bring your own bottle(s).

I only shop at other horrible corrupt American grocery store chains with flimsy products and like their bathrooms, I dread thinking about what lies within.

Edit : It also doesn't help that searching for "Walmarts in my area" turns up Targets for some reason.

[Dusty Ol' Man]

Originally Posted by Lil Duck

I only shop at other horrible corrupt American grocery store chains with flimsy products and like their bathrooms, I dread thinking about what lies within.

There is always a countertop RO unit. Ray sells several models.

[Roberta]

Originally Posted by Dusty Ol' Man

There is always a countertop RO unit. Ray sells several models.

This is likely a very temporary problem - the usual water source in the SF area is a reservoir that is supplied with snow-melt water, some of the best water around. (Valley very near Yosemite.) But at the moment, I suspect that everything is pretty frozen. A situation that should be resolving itself in the next month or so... we hope that it does so gradually and gently, there's enough snow to cause some really nasty flooding if the warming is too fast.

[Dusty Ol' Man]

Originally Posted by Roberta

This is likely a very temporary problem - the usual water source in the SF area is a reservoir that is supplied with snow-melt water, some of the best water around. But at the moment, I suspect that everything is pretty frozen. A situation that should be resolving itself in the next month or so... we hope that it does so gradually and gently, there's enough snow to cause some really nasty flooding if the warming is too fast.

I used to live in Modesto. Some days I wish I still did. I remember some miscalculation of snowmelt in past years caused one reservoir to overfill. I think having your own source of RO takes the guesswork out of watering needs. I realize some folks have many more plants than I, but the fact remains that city water quality, regardless of source, is variable. I've been watching the Sierra snowpack and praying for a slow melt.

[PuiPuiMolcar]

I dont know if this is a norcal and centralcal thing but down here in Socal we have waterstore (where mostly immigrant family owned) that sell drinking water or just RO water. They permit bigger water container in any shape, and I usually refill my 5 gallon bucket at the local uncle's shop for $1.25. If you don't have them, you can also get larger RO water quantity from the local fish stores, aquarium hobbyist need RO water for their fish and plants so I can safely say that you can use it for orchid as well.