Drinking RO/DI?

disc1 said:
See post #5 in this thread.
Click to expand...

Interesting, but still doesn't answer the question. Does flushing your system regularly reduce the bacterial count in your membranes? If so how long should one go about flushing their system? If you are making water daily or monthly, what measures should you take? That is what I was asking.
 
How so? If I adjust my valve so that all water from my tap is to go through the waste line and not through my ro line, isn't that chlorinated water flushing throught he system?
 
Not if your system is configured properly. Any water that reaches the "in" port of the RO membrane housing should have been through the carbon block (where the chlorine is removed).

Russ
 
So I guess, we could remove said membrane, carbon block and run the system for awhile to clear the lines and housings. That way you get the clorine and cloramine to all parts? And just make a habit of rinsing out regularly kinda like a camelbak? Also, Im leery on the supermarket water dispensers. I have never seen a company service ours. Don't the uv bulbs go bad? The owner of the market doesn't even know. He simply stated, that "water machine" has been around for years... uhhhgg.
 
I change filters every 6 months and membrane every year. When I change membrane I remove all filters and pour bleach in all three filter bowls and membrane housing. I remove media from Di filter and reinstall empty. I turn on water and open all 5 faucets until I smell chlorine. I let sit for 3 hours and drain. I clean all filter housings and flush system 3 times before adding new filters. I have a 3 gallon storage tank undersink and a 20 gallon well pressure tank in laundry room to store water. This gives me 12 to 16 gallons of water at all times depending on cycling of on/off valve on to unit. I have fridge and spigot plumbed to in ro and two tanks and seperate spigot on Di. System is always running and always sealed. Installed ro in 2000.
 
You want to avoid use of pressurized storage tanks with RODI systems unless they are plumbed such that RO water stored in the tanks never makes it to the DI. Don't store DI water in a pressurized tank.

Russ
 
Forgetting about the bacteriological concerns for a minute - my question is why would you do such a thing regularly? Don't most systems have a 3:1 or 4:1 waste ratio? So for every gallon of filtered water, you are chucking 3 or 4 gallons of waste literally down the drain (or watering the plants etc). If you're on a water meter or a tiered billing system - won't this get expensive?

I can certainly appreciate taste concerns. The water where I lived up to 15 years ago was fairly soft and neutral while anyone could walk on my current tap water - it's that hard. With that in mind, the output of my refrigerator's filter is quite pleasant (while still being hard) and without the waste.

And IME RO/DI makes excellent tea. :)
 
Wow, this is the first I have heard of drinking RO/DI being a problem. I grew up on well water and it wasn't chlorinated. Wouldn't distilled water sold in stores would be subject to the same problems mentioned?
 
BuckeyeFS said:
You want to avoid use of pressurized storage tanks with RODI systems unless they are plumbed such that RO water stored in the tanks never makes it to the DI. Don't store DI water in a pressurized tank.

Russ
Click to expand...

It's a rubber lined food safe tank. What are concerns?


From tank web site
The pressure tank is actually two containers in one. The upper shell is the air chamber. The lower container, consists of a butyl rubber diaphragm and polypropylene liner. This design seals in air charge, separating air from water, which eliminates the need for an air volume control device. Liner eliminates bad taste and odor.

All materials that come in contact with water comply with FDA regulations. Full five year warranty.
 
Randy Holmes-Farley said:
What the concern? Corrosion?
Click to expand...

Hi Randy.

Corrosion is a concern, but the primary thing that concerns me is the back pressure from the tank.

If for example your feedwater pressure is 60 psi, a full pressure tank will provide about 66% to 85% (assuming the system has a standard or a high pressure hydraulic shut off valve) of that in back pressure. So the net driving pressure (exclusive of the osmotic pressure) would be 9 to 20 psi. So as the tank fills, the back pressure increases, and the net driving pressure decreases. You can imagine what sort of rejection rate (and shortened DI life) you'll get from your membrane at 9 to 20 psi.

An atmospheric tank is a much better option where permeate TDS is critical.

Russ
 
Sure - we use pressure tanks in our Reef/Residential Series RODI's, and in our Residential Series RO's.

It may be counterintuitive but drinking water is one of those situations where TDS isn't critical. There's not a problem with using the tanks - you just have to make sure your system is configured such that water from the tank never makes its way back to the DI. The DI should be fed directly from the RO. We can email you a plumbing diagram if that would help.

Russ
 
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