How to choose a Reverse Osmosis device?

[InjectTruth]

I am looking into getting an RO filter, and after looking around on ebay and the web, I am very confused. I see models that look 10 times stronger going for less than half the price of units with less filter stages.

What are the standards I am looking for when purchasing an RO filter, to make sure I am getting the quality of water that I need. Buying distilled water has gotten old.

 

[GreenyGreen]

I personally do not have much knowledge on the different levels of purification but generally a RO filter takes any quality of water and brings it down to under 30ppm which is more stable then very high ppm hard water in rural areas. The criteria I was most interested in when I was picking out a RO unit was how many gallons per day it was capable of producing because depending on the size of your grow you might need a larger unit. I went with one that was capable of 20-30 gallons a day run constantly (not recommended by the product manual) or more reasonably 10 gallons if I could be around to empty the 3 gallon storage tank it had every few hours as it filled.

 

[badugi]

When I was researching some RO units some time ago, I had the same question as you (the eBay 6-stage systems being 1/2 price or better compared to SpectraPure and other 2-, 3- or 4-stage units)... and found that the SpectraPure and other "pricier" brands almost always performed better, with the eBay system not getting all that great of a review around here. It's been about 2 years since doing that search, but I'm sure the information is still here. Hope I was able to recall enough details from my memory...

 

[FreezerBoy]

Seen this? DIY RO Filter

 

[coolx]

years ago I got a 100 gpd 6 stage system with Deionization, UV light and permeate pump for $350. I get 0 ppm. Works awesome, getting another for about $250 tomorrow. Permeate pump is important as it reduces waste water by 90%. Normally 5 gals of water gives you just 1 gal of RO water.