RO system questions

[Weetamoo]

I'd appreciate any advice anyone has to offer on how to determine what is a good RO system for me.
I have well water, and I want to get one to put under the sink in my new greenhouse addition. (I got a TDS meter and it reads about 140 - 160 at different times). I'm not sure what to look for. I want something easy to maintain and use. my humidifiers in my house get a pink slime inside if I neglect to clean them for a few weeks.
Thanks, Clara

[raybark]

Clara, I’ve been using, building and selling RO systems to growers for 30 years.

First, the fact that you are on a well means no chlorine, so you can use a 4-stage system. Those “stages”, in order the water passes through them, are a sediment filter to remove suspended solids, a carbon filter to remove organic chemicals, the membrane itself which extracts the dissolved solids, then a so-called “polishing” filter to capture any organics passing through the membrane.

A word of buying advice: get a system that uses industry standard components, not proprietary ones. Sediment filters should be replaced every 6 months, the carbon once a year, and the membrane and polishing filter every two. Standard parts can be obtained at your local big hardware stores or online, but proprietary ones make you beholding to that manufacturer and vulnerable to their pricing and potential availability issues.

While there is one stream of water entering the membrane, there are two coming out - the purified water and the flush water, which carries away the rejected solids. The flush water can be used/disposed of in any number of ways. Some route it back into the well, some use it to water gardens and other less-sensitive plants. Others let it drain to the greenhouse floor where it raises the humidity. In my greenhouse in Doylestown, mine kept a small, artificial pond just outside the structure full, providing water for local fauna as well as a home to a million frogs.

RO systems are not “on-demand” water supplies. A 100 gallon-per-day system sounds like a lot, but that’s about a cup/minute, and you’re not going to water anything at that flow. Plus, systems are rated at 77F, 65psi water, and yours is not likely to be that warm or at that pressure, so the output will be reduced. That means you’ll need some sort of water storage and a means to deliver that to your plants. Residential systems typically come with a 3-, or 4-gallon bladder tank, but that’s not sufficient volume for more than a few plants.

I’d be more than happy to spend some time with you on the phone to provide more details and help you decide on appropriate production and storage capacity, whether you buy from me or not. (Since retiring and moving to NC, the RO part of my business is as much for the convenience of past purchasers needing replacement parts ata decent price as anything else.) Send me a private message with your phone number and a convenient time.