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Reverse Osmosis

Discussion in 'Everything Else Orchid' started by Alexis, Nov 6, 2009.

  1. Alexis

    Alexis New Member

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    I currently water with well water, which is pumped from the same well as my house water. Our well water is actually quite good, but it's high in calcium and other minerals (no chlorine) which causes significant leaf spotting. It's also very alkaline. My plants grow well, but it's time to improve my culture further. I'm considering R/O, but am going to need a pretty big system. My shadehouse is 24'x36' and I water nearly every day for 10-15 min.

    Anyone here have a system they recommend? I'm looking to those folks who have greenhouses/shadehouses, and/or use a high-capacity system. I've looked at a number of articles online, such as the one found on Ray's site, but if anyone has a really great source of info that pertains to this specific topic, I'd appreciate the lead.

    TIA!
     
  2. Clark

    Clark Gator Member

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    The manufacture of my system is no longer around. Sam's Club here has a system they sell and have been selling for close to 8 years now. Mine discharges to a 55-gallon plastic drum. A sump pump from Lowe's pumps the RO water out (the first one I bought back in 2000 just died twoo weeks ago). Attached to a hose with a spray head I use it to water the greenhouse.
     
  3. Candace

    Candace Kept Woman Supporting Member

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    Alexis, it's not necessarily that you need a big system, but you will need some larger storage for the water that you want to be ready to go. I think I've got either a 75 or 100 GPD but used to have a 50 GPD and that was fine. I have 20 gallons of pressurized tank that I store it in, but any plastic drum would be fine. The pressurized tanks that I have mainly are to get the water into my sprayer without having to use a pump.

    Most people who have RO systems put the drums or tanks under their benches so as not take up too much space and to keep the water at g.h. temp.

    I bought my 5 stage system over the net at www.waterfiltersonline.com They've got quite a few to choose from.
     
  4. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Alexis, I have a system that I have cobbled together that works very well for me for the greenhouses and another one "out of the box" at work. They are really very simple once you decide to do it. It makes such a huge difference in the plants that it will be worth the effort.

    The first thing to figure out is how much water do you need on a daily basis. If you use a proportioner of some kind to fertilize it is pretty easy to figure out how much water you are using by how much concentrate the is sucked up.

    I would also recommend a well pump as opposed to a sump pump so you can have decent pressure to water or mist with.
     
  5. Jon

    Jon Mmmm... bulbophyllum...

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    The limiting factor on how much RO a system can produce in one day is the rate of the membrane. Lots of home systems have a 100 gallons per day rating, so a couple of membranes in parallel would work great, I'd think. For water storage tanks, go to a local car wash and get a couple of the old concentrate drums and rinse them out with vinegar, then rinse with baking soda for good measure. They're great for water storage, and they're generally pretty inexpensive. And, like Marni said, get a shallow well pump. The pressure is much better; you won't regret it.
     
  6. Alexis

    Alexis New Member

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    Thanks for the ideas, everyone. I know my husband can do this type of installation with his eyes closed; I just want to have my ducks in a row before I pitch it to him!
     
  7. harrywitmore

    harrywitmore Member

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    My only problem with RO systems is the amount of water that is wasted in the process. I found that for every gallon of RO I got I ended up with 5 gallons of water that was not usable on my plants. Now, if I had a way to return this to my well then that would be great. If I had a place to store it like a pond and use it for watering landscape that would be good too. But, I have neither and since I have a well I really didn't like the idea. So, I decided to catch rainwater instead and it seems to work well. I'm currently storing about 600 gallons in a series of tanks. I will eventually get the all plumbed together but haven't yet. I have a well pump and tank to provide the pressure and my intent is to switch over to this completely. If I had a 1000 gallon tank I could fill it easily in one rainstorm. I have tested the water and it is almost identical to RO water but with a slight stain mostly from leaves.
     
  8. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Harry, if you put a valve on the discharge line you can stop it down until you discharge 2 gallons for every one you keep. If you try to go lower than that you go through ro membranes really fast.
     
  9. Candace

    Candace Kept Woman Supporting Member

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    Harry, we are metered here, so we pay for our water use. I have the excess going into my evaporative cooler. It makes me feel less guilty about the run-off. I'm sure it somewhat decreases the lifespan of the cooler pads, but I think it's worth it.
     
  10. Aceetobe

    Aceetobe Member

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    You can also return the waste water to your hot water heater, resulting in less waste.
     
  11. Ray

    Ray Orchid Iconoclast Supporting Member

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    There are many ways to skin a cat.

    The tank idea for water demand is number 1. The system can create water while you're not using it, so you simply store enough to use.

    Choking down the flush water will reduce the membrane life, even at a 2:1 ratio. Finding an alternate use for that water is a better idea. I fill a pond for the local wildlife; the overflow makes its way back into the aquifer. The hot water system is another great idea, although it does take a pump.

    If your demand is really high, you can go with a GE Merlin system that is rated up to 700 gpd, but they are quite pricey and the replacement parts follow that.
     
  12. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    If I regularly change my prefilters (to take out chlorine) I get about 18 months to 2 years out of an RO membrane. At about $40 for a good quality 100 gpd membrane, even using a couple of membranes in parrallel it is a lot cheaper than paying the meter rate for the excess water. Stopping it down leaves you with a more concentrated ppm in the discharge water, but I run it into a swale in the back yard where birds drink and bath.

    If chlorine gets to the RO membrane they go bad before you can turn around.
     
  13. Armando

    Armando Hobbyist gone wild

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    is it easy to store a tank under the bench without getting watering water in it? where do i find low height tanks like that? Does a well pump need to be manually powered on every time it's used or can be left turned on? Can the pump be exposed to watering water or needs to be sheltered? sorry lots of questions!
     
  14. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Armando, if your benches are very low, it might be hard to find barrels to fit underneath. Some people will dig out the ground under the bench so a deeper one can be fit underneath. Using a barrel with a good lid and plumbing through the side with through-bulkhead fittings at the bottom to connect them will let water flow from others in a line. A shallow well pump has a bladder tank that holds a quantity of water. When the pressure drops below a certain point (that you can set) it turns the motor on, pumps up the pressure until it shuts off at the cut out point. It can not be exposed to water, it needs to be dry.

    I know that lots of growers like to put barrels under the benches because it saves space, acts as a heat sump and keeps the water at a more even temperature. I would never do that. I think the most important place to get air circulation is under the benches and the barrels would block that. I have 5 fans in my 21 x 21 ft greenhouse and 4 are on the floor.
     
  15. harrywitmore

    harrywitmore Member

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    All are of the above is good advice and I considered it all before going for rain water. I have an expandable system that gets replenished whenever it rains. The water seems to be almost as good as RO water and it's free. To get a cleaner supply I'm adding gutters to the greenhouse where it runs off plastic and not shingles. I still have a ways to go to get it totally operational but I think it's going to do well.

    I did some side by side test with the water on identical plants from the same vendor. I watered one with RO and one with rain water. There seemed to be no difference in the health of the plant over a period of 6 months. While this wasn't a scientific test it did give me enough confidence that the water is good. Certainly better than my well water although it was not all that bad.
     
  16. Ray

    Ray Orchid Iconoclast Supporting Member

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    Unless you live in a fairly industrialized area, or one with lots of automobile use, rainwater is just about as pure as it gets.

    Armando, you'll want a pump with a bladder tank and pressure switch, or you're going to have to manually turn it on before watering, and off afterward. Otherwise, you'll burn it out in no time.
     
  17. Aceetobe

    Aceetobe Member

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    Two observations - #1 Marni has Hetch-Hetchy water which is around 50-100ppm out of the tap. I'm assuming this contributes to her ability to allow the membranes as long as they do. #2 California has "seasonal" rain pattern which doesn't allow us to count on rain water collection. I can and do collect several hundred gallons of water, but that only lasts me a couple weeks after the rains stop (think march/april). We don't get more rain for 9 months. If you live in a place (aka not the southwest), then rainwater collection is a great way to go.
     
  18. harrywitmore

    harrywitmore Member

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    50-100 ppm of what? Chlorine? Since Alexis lives in Florida where there normally is no scarcity of rain I was thinking of that when mentioning a catchment system. Even so, a catchment system is only restricted by it's size since even a small house during a heavy rain can exceed most any size tank.
     
  19. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Actually, I don't live in San Francisco and so am not on Hetch Hetchy water. Though a friend in SF had a lot of destruction to plants to sensitive plants when the SF water district switched (without notice) to adding ground water for awhile at times. SF also adjust the pH, but they use potassium hydroxide.

    I used to have great water, but the water district here in the Russian River watershed started adding sodium hydroxide to the supply in 1996. That raised the pH from 6.5 to 8.4. So it is mainly sodium that I am taking out. Perhaps that is why my membranes last a long time.

    About the same time I started having a decline in my collection, Ann and Phil Jesup told me they were switching off tap water. The too were having a serious deline when they notice on the water bill that there was a note not to drink the water if you had a heart condition. My bill frequently comes with notes like: Your tap water doesn't contain any more sodium than the average mineral water.

    I had a friend on the central coast of California who used to catch water. He had a 30,000 gallon tank buried on his property and then added another that was about 10 or 20,000 because the rainfall is not throughout the year and we have been in and out of drought.

    If a catchment system will work for you, they are great. It won't work for me here. I have two friends with catchment systems who have had there tanks drained by plumbing mishap while on vacation. Image loosing 30,000 gallons!!
     
  20. harrywitmore

    harrywitmore Member

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    Well we all use a catchment system. Some catch their own and some don't.

    I once had a pipe break in the greenhouse and it put about 1 foot of water over an area about 50'x100'. That's about 5000 cubic feet of water. That's about 40,000 gallons so yep I can imagine it. That all came out of my well overnight.