Thanks for the reply.

We had a RO system in the past, and I miss it, hate having to clean the water boiler...

The reason she doesn't like RO is because she wants "natural water". She heard that RO will leach minerals from your body, and that alkaline water may not be good for you... I didn't research these topics but I wouldn't be able to convince her otherwise anyways. So yeah...back to my question:

I know without the membrane it's not RO anymore, but that is fine. I just want a cheaper to maintain system that filters better than a Brita jug. (The eSpring is just like a brita jug but with UV lamp, btw). So I thought of modifying a RO system because of the multiple filters and that it provides the same level of convenience we are used to now.

More feedbacks please =)

Have you seen the Nahla Pure filter? Lasts 3 years and takes up little room. Looking to get rid of the Brita.

The only thing I can add to respond to your original post is that you don't need a storage tank so long as the sediment and charcoal filters can pass the water flow rate that you expect from your pot filler or other filtered water delivery faucet. If I were assembling your list of parts, I would leave out the tank until I had determined that it was needed to meet my flow rate expectation.

Standard size filters (4 x 12-inch canister type) connected to your faucet by 3/8 tubing (copper for mechanical hazard protection or 3/8-inch food grade polyethylene) will provide good enough flow rate for kitchen use in my opinion. These filters can be located anywhere convenient for mounting. John Guest fittings for poly water supply lines make installations easy. See, for example, Portage Specialty Co. for fittings and tubing. [portagespecialty.com]

You may want to put a valve in the line (besides the ones needed to isolate the filters so that they can be changed) for restricting the flow if it turns out to be higher than the filters are rated for. Charcoal filtering works best if the flow rate is modest. Also, include a means to flush the replacement filters if you don't want to do this at the sink.

As for RO leaching, there are World Wide Web links that will support every position that one can imagine on every subject ever raised. A quick DuckDuckGo search provided many examples. This one is reasonable.

https://elkenforlife.wordpress.com/h20-purifier/reverse-osmosis-water-filter-guide-truth-lies-minerals-your-health/

I have an RO System with two membranes in series (brine wise) to maximize RO production for a given brine flow. It uses a brine-fed peristaltic pump to keep the RO supply pressure up and and the RO output side of the membranes pressure low for best efficiency. In this case a pressure tank (I have two, one well pump sized) is needed. My RO system feeds three sinks, a centrifugal humidifier, and a refrigerator/freezer ice maker. My specific RO membrane filters, pump, and control components come from Spectrapure. Pre- and post filters come from various other sources.

http://www.spectrapure.com/

Sediment filters can be purchased at hardware stores and plumbing distributors. Charcoal filters can be found by searching the Internet, with some savings possible when buying a case at a time. K-X Technologies is one possible source.

A possibly not commonly realized advantage of RO water is that it can be used to final rinse hand-washed wine and ale glasses. When hung, the glasses will dry taste free without any water spots. An RO rinse would probably work for a final automobile rinse, but I haven't yet embraced that degree of extravagance.

kas

Sorry for the late reply. I completely forgot about this thread because work and some sudden repairs at home took up most of my free time.

I want to thank dbabrams and kaseki for replying to my posts. I got some great information and learned of a product I didn't know about before (the Nahla Pure filter). I think I am going to try out my initial plan above first and then go from there.

@kaseki: That is an awesome set up you have there. Never heard of a peristaltic pump before. What made you choose peristaltic pump and not a more common permeate pump?

Also for your tanks, do they use the standard butyl rubber/polypropylene lining? I am sure they are safe but just wondering if there are any other storage options here... Why don't they make glass tanks? lol

Thanks again!

My pump pumps permeate using a peristaltic pumping scheme, as far as I can tell. So it is a permeate pump. Specifically, the pump "motor" uses the energy in the brine pressure before it is released to an atmospheric pressure sewage drain line. The load side accepts low pressure RO output of the RO membranes and pumps it to my storage tanks at a tank pressure of around 60 psi, same as I regulate the system input pressure to.

The peristaltic pump is not otherwise powered, but there needs to be a control system to shut off the RO system house water supply when the desired output pressure is reached. Otherwise, water would be continuously drained to waste.

One tank ("the small white one") was part of an early RO system that I determined was too inefficient to avoid massive reconfiguration. It is plastic on the exterior. I don't know what the air bladder or inner coating, if any, are made of. I use this for kitchen water storage. It receives water through a charcoal polishing filter, and has a significant rate of water replacement. If there is any leaching, I can't detect it.

The other tank ("the larger gray one") was purchased from a well company, and was the smallest of the well tanks that they had. It is epoxy fiberglass wound on the outside. I don't know what the interior is coated with, or what the air bladder is made from, but it had to meet well water safety requirements. This tank supplies my humidifier and a family room sink, in the latter case through a charcoal polishing filter.

A glass tank would have to be pretty rugged for high pressure, and would probably require by law an exterior safety shell. Fittings interfaces might be tricky.

For adequate tank inertness, a properly welded food grade stainless steel tank would be fine. However, due to water's incompressibility, usually bladders are used in water pressure tanks to keep the air mass constant; just using an air space at the top will lead to absorption by the water with the result that the buffering volume will slowly decrease.

kas