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Reverse Osmosis Advice


A leuco by any other name would still be as glutto
Okay fellow TFers, I have a quandary: what do I need to know before buying a reverse osmosis unit? I am tired of collecting water off my air conditioning coils, but I don't quite know what I am in for.

Some background insight first, I guess. I have about twenty to twenty-five containers of Sarrs right now ranging from quart size to cooler size. Additionally, I have a couple coolers full of flytraps and Darlingtonia. Also, I have a growing number of Neps and dews. Couple all that with a few orchids and I can easily justify a RO system. Would a typical system be good enough for two or three gallons a day on average and up to ten or twelve a day when I want to replant (washing off dead plant material and media, rinsing containers, and wetting new media)?

I want a typical under sink unit I think, but I am not enamored with the idea of drilling a whole in my sink to mount a new spout, nor do I relish the idea of replacing a perfectly good faucet with one of those fancy aerator-faucet-in-one combos in order to clear the occupied accessory hole on my current sink. Are there other options here? Is there a way to run the output in line to my cold water and just always have RO water with the cold handle?

Finally, how long will a membrane last? I know filters will vary on water quality (I get about three months on my cheapy cartridge filters now), but do the membranes go a lot longer?

The local Sears has a complete unit clearance priced at $84 from the original $168. I am thinking about jumping on it, but I wanted to ask some questions first.
Unless your tap ppm is ridiculous, get a unit with as few filters as possible. The plants don't care about that extra 10ppm the second filter skims off. My first unit had a post-filter which just took up space and gave me another thing to replace. I saw it as useless, but it's hard to find a unit without one. I finally discovered my ideal unit a few months ago: nothing but a pre-filter and a membrane. I bought the rest of the parts I needed on eBay (check valve and high-volume auto shutoff).

Volume per day depends mainly on your reservoir. My first unit was 75gpd, and to get 12 gallons out of it would have been a challenge because my tank is only 2 gallons. My current unit is 200gpd and 12 gallons is a piece of cake. I just filled a 5 gallon container in about an hour. If your reservoir holds the maximum amount of water you could ever need in one day, any RO unit will do the trick.

My first unit's membrane lasted maybe 7 years, and I didn't do a good job of maintaining it. Your diligence with protecting it from sediment and chlorine will determine its lifespan.
Thanks guys! Great info on both accounts.