Best place to purchase RO/DI unit...

Won't go with anything other than SpectraPure. :thumb_up:

 

Is it slow because of low water pressure, slow because it's winter, or is it always slow?

 

Having not done enough research on the right end of my RO/DI purchase I am now stuck with a half decent ebay unit for what is arguably the single most important element of this hobby- the water. In hindsight I would have bought a Spectrapure. Just based on the facts, it is a superior system and their superiority is measurable. It will cost me more down the road to upgrade mine than to just have bought the Spectrapure. To me, the batch tests set them apart. I know of no other company that does this. Read about it on their website. Try to find a review anywhere with a negative comment about them- you won't. Every one who has them loves them.

 

Two things have a major effect on the output of a RO membrane, water pressure and water temperature.

Russ, at Buckeye Field Supply has put together a nice simple calculator found here on his home page:
http://www.buckeyefieldsupply.com/calc.asp

Plug in a 75 GPD RO membrane and Dow Filmtecs test data of 50 psi and 77 degrees F and you see you get 75 GPD. Now play with the numbers and you can see how either or both can really skew a membranes GPD.

One thing to keep in mind when your RO is running slow, colder water, while it slow production also produces lower TDS. So, warming the water is not a good idea, a booster pump is a much better choice as increased pressure will offset lower temperature. That plus a RO membrane melts at anything over 113 degrees so a shot of hot water could ruin a membrane in a heartbeat. Some people try blending or tempering the water but remember being in the shower and someone flushes the toilet or starts the washing machine on cold? You got your tush scalded and thats the same thing that will ruin a membrane. Go the booster pump route if you want to increase GPD.