ro/di system

[rburn99]

It seems everyone agrees not to use tap water (although it always worked fine for my FOWLR system years ago). I don't know anything about ro/di systems so I wonder if I can get some info on them. I've done some searching but everything I find seems to assume you know everything about them already and only give specs or hype.

First of all, I see this on ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 83005&rd=1
Is it a good system? If not, why? ( for that matter if so, why )

Second, what is involved in setting up/using them? I see they need to be connected to your faucet. I gather that 90 percent of the water used from the faucet goes down the drain? Isn't this a large overhead? 1000 gallons of water to get 100? (I don't know what the city charges for 1000 gallons of water). So how do you dispose of this water? Do you have to splice into your plumbing? Lay a hose in the sink? Use garbage cans for the overflow? I assume it takes time to collect 100 gallons with this method. So do you just run this all the time? If so wouldn't that make a big dent in your water pressure for showering, washing, etc..

Third, the cost of the water aside, what other costs are incurred? What maintenance is involved? Filters? Water storage? (can this water be stored indefinitely? A pool will turn green in just a couple days without regular treatment. Is 'pure' water fine to collect then?

Thanks for the help,
Robb

 

[ChrisRD]

That looks like a nice system. I particularly like the refillable DI cartridge.

There are many ways to setup one of these units from using a faucet adapter and just connecting it to your sink, to hard plumbing it right into your house water lines. It's really up to you how you want to set it up. As long as you have a water supply to the unit and somewhere for the waste water to go it really doesn't matter.

Typically most RO membranes reject around 3 or 4 to 1 when working properly, so in your 100 gallon example it would take about 400 gallons or so to make that much water. The rejection rate will vary depending on input pressure, water temp, and restriction on the waste line.

Also, keep in mind that the "waste" water has passed through sediment and carbon filters, so it may actually be better tasting than your regular tap. It's perfectly safe to drink or use for watering plants, filling the washing machine, etc. You can also just let it run down the drain (or plumb it to a house waste line) if your lazy

As for running the unit - you don't have to run it continuosly. You can just turn it on/hooki it up when you need to make a batch of water. It's a good idea to get a "flush kit" to flush out the RO membrane periodically - supposedly helps it last longer.

As for storing the purified water - any food safe container is fine to store it indefinitely. I generally make sure there's some type of sealable lid on it though.

As for maintenance - the catridges/membranes/resins need to be replaced periodically. How often will depend on what condition the water is in that you are filtering.

HTH