Distilled versus R.O. - Orchid Board

utah · #1 08-29-2008, 02:17 AM

My water here is *VERY* hard

and, since I'm *slowly* building a greenhouse, I'm looking at finding a better source for my water. I've been using the hard water this summer but the babies need something better.

I've looked at the R.O. systems and, although good, I don't like the idea of "wasting" so much water in the process (only getting about 1 gallon of "good" water while having to "dump" about 4 gallons of "bad" water). I'm in a desert so I'm not so thrilled about wasting so much water - even if I use it for other purposes.

Besides, during the very cold winters here there isn't really anywhere to "use" the "bad" water.

Has anyone used a distiller at home? The ones I've seen only produce a small amount of water after a lot of time and energy and I can't afford an expensive, large unit.

Anyone with experience, sources, or good ideas?

Ray · #2 08-29-2008, 08:22 AM

Personally, I use the RO "flush" water (a better term than "waste" in my opinion) to keep a small, artificial pond full outside of my greenhouse.

In the summer, the birds and frogs love it, and in the winter, we get all sorts of wildlife using it as the water supply.

Other alternatives are letting it wet the GH floor for humidification, or for watering non-orchids.

AND...if you still don't like those ideas, you can buy a so-called "zero-waste" adapter. It's really nothing more than a pump that forces the flush water into your household hot water supply, but it is a good idea. I've been thinking of adding them to my RO product line, but so-far, nobody has specifically inquired about them.

Jerry Delaney · #3 08-29-2008, 05:48 PM

You might also consider renting or leasing a deionizing system using a "mixed bed" resin. Just remember that the water coming from the unit is usually quite acid, but since there is literally no to very little ions present in the deionized water that it has no buffering capacity and will take very little pH Up to adjust it to a optimum pH. Ray, I had never heard of this trick of cycling the "flush" water into the hot water system. Sounds like a good idea. Very similar to recycling the condensate water from a boiler system. Would a system like this cause any problems with a water heater as far as hard water deposits?

Ray · #4 08-30-2008, 09:48 AM

Certainly it will contribute to the dissolved solids content of the supplied water, but the question is, is it significant?

Let's say your water is 200 ppm solids to start with, and your particular RO system as a 4:1 flush ratio. That means that in an "ideal" situation, the flush water is 250 ppm, and the RO steam 0.

Now then, if you average producing 20 gallons of RO per day, that means you are pushing 80 gallons @ 250 ppm into your water line containing ??? gallons of 200 ppm water. That much is just math, so you would need to know how much hot water you consume to figure out if it's a significant addition.

I have never read any instructions about installation of them, but if you inject into the hot water line (after the heater), it's no issue, and if you inject it into the cold-water line (whether going into the heater or not), in effect your putting it into the entire water system, meaning that it's VERY diluted.

It would seem that putting it into the hot water delivery line is the best, as the temperature keeps the solids dissolved (probably only an issue if you have REALLY hard water to begin with), and there is no impact on the heater, but if you're not using the hot water, does the pressure just build and build? And what happens when the back-pressure stalls the pump? Maybe there's a pressure switch that only pumps the flush water when the hot water is on?

Jerry Delaney · #5 08-30-2008, 06:16 PM

Sounds reasonable but complicated Ray. For now, think I will stick to my tap water!

Ross · #6 08-30-2008, 06:25 PM

Ray, how about hot water that is heated after going through a softener. The 200 ppm solids is now sodium (primarily) which feels soft but isn't great for the heart or the pipes (thus plastic). Moving the "rinse" water from the RO to the heater line would partly negate the intent of softening the water, correct? Our flush water goes through city treatment for reinjection to the ground water. Pretty much a closed system, as far as I have been told. Right now I personally don't worry about the few gallons flush water I "waste" since watering the lawn with city water puts a whale of a lot more water into the surface of the graound than I "waste".

utah · #7 08-31-2008, 09:21 PM

Hi guys

Don't want to get in the middle of an argument but my greenhouse is not connected to any water supply. I will have to bring in water from a garden hose then store it in barrels so pumping any excess water into my hot water system isn't going to work.

I know that I'm going to have to "process" and store quite a bit of water in the greenhouse for the winter. RO seems to use produce a lot of "excess" water that I can't pump into any system (and can't spend all day walking around dumping it on plants in the yard). The distilling systems seem more practical but make such a small amount of water while using quite a bit of energy.

So, for a person in this circumstance (with LIMITED $$$), can anyone offer any good advice?

Thanks!

Ray · #8 08-31-2008, 10:26 PM

Ross, I agree that putting the flush waer in the hot water supply does negate the softening, but again, to what degree?

Utah - 1) What argument? 2) If you think for a moment that you're going to store a whole winter's worth of water, you're either delusional (orchids can do that to you) or growing only one or two plants.

If you want pure water, you can 1) buy it at the grocery store, or 2) produce it yourself. If you choose the latter, you can go with RO, distilled, or DI, and it's up to you to figure out what's the most economical under your circumstances. I'd bet on RO, using the flush water to humidify in the dry winter, but you're in a better place to judge that than I.

If you don't have a water supply in the greenhouse, you had better fix that before the ground freezes. Life will be much easier when you do.

utah · #9 09-01-2008, 01:00 AM

Quote:

Originally Posted by Ray

Ross, I agree that putting the flush waer in the hot water supply does negate the softening, but again, to what degree?

Utah - 1) What argument? 2) If you think for a moment that you're going to store a whole winter's worth of water, you're either delusional (orchids can do that to you) or growing only one or two plants.

If you want pure water, you can 1) buy it at the grocery store, or 2) produce it yourself. If you choose the latter, you can go with RO, distilled, or DI, and it's up to you to figure out what's the most economical under your circumstances. I'd bet on RO, using the flush water to humidify in the dry winter, but you're in a better place to judge that than I.

If you don't have a water supply in the greenhouse, you had better fix that before the ground freezes. Life will be much easier when you do.

Honestly I'm not delusional, just trying to make the most of the limited resources I have. This greenhouse has taken every last penny I have. Oh, and I don't just have one or two orchids, I actually have about 200+ orchids. I don't have the option of putting a water supply to the greenhouse since that would entail ripping up concrete and, like I said, I'm on a very limited budget.

I *know* that I'm not going to be able to keep a winter's worth of water in the greenhouse but I'm hoping for a few week's worth in 55gal drums. I can't use the flush water from a RO system to humidify since it contains the same hard water problem that I am trying to overcome and I've killed off far too many humidifiers with tap water and my orchids are already covered in hard water deposits from the misting system (which I hope to resolve with this new system).

I'm just looking for experience from others in my situation before I spend a few hundred dollars on a water purifying system.

Okay, I'll just have to weigh my options. Thanks for your help.

Jerry Delaney · #10 09-01-2008, 04:00 AM

Quote:

I'm just looking for experience from others in my situation before I spend a few hundred dollars on a water purifying system.

Okay, I'll just have to weigh my options. Thanks for your help.

Don't give up Utah. I don't know exactly where you live in Utah, but Culligan used to rent deionizing units. I used one for about 15 months after first moving to Bakersfield. I leased it from Culligan for ~ $30/month. I have no idea if they even still lease these units. If your water is really hard, you might consider passing the water through a softening unit before putting it through the deionizer as you can regenerate the softening resin yourself and it will greatly extend the life of the deionizing system. If there is no one near you that will lease the deionizing unit, you can purchase refillable cartridges and buy new or regenerated DI resin. You can do the same thing with the softening unit. This would allow you to simply use a ordinary garden hose from your house to the unit (either in your house or the greenhouse. There is zero waste using such a system except for what water you will use to regenerate the softening resin. Distilled water will also work just fine (I'm not sure if it would make any difference but personally I would avoid using a copper still if you go that route) but I feel you will find that stills are really energy hogs. Good luck Utah!